Aircraft take-off and landing system and method for using same

ABSTRACT

An aircraft take-off and landing system, wherein a symbol of a specified configuration is employed as an instrument means for take-off and landing. 
     This symbol is formed by directed extended references made up of electromagnetic pencil beams with a wavelength which is within atmospheric windows, produced by at least one source of electromagnetic radiation, positioned on a flight platform. The electromagnetic pencil beams are oriented in space so that they determine the configuration of a symbol and, simultaneously, indicate the course and glide slope of an aircraft take-off and landing path, set a spatical take-off and landing corridor wherein this path lies, and show additionally various limits of a take-off and landing platform or various marker points of an estimated take-off and landing path. The method of aircraft take-off and landing, according to the proposed system, consists in flying an aircraft on a symbol of a specified configuration, its distortions being indicative of the aircraft&#39;s deviation from the estimated take-off and landing path and their magnitude being indicative of the deviation direction and value. The proposed system may be made purely instrumental or visual, permitting both automatic and manual flying of an aircraft and is 100 or 1,000 times more accurate than conventional systems with localizers and glide slope transmitters. The aircraft flying method, according to the proposed system, is characterized by exceptional simplicity and reliability, it remains consistent at all stages of a take-off or landing path.

This is a divisional of application Ser. No. 622,762, filed Oct. 15,1975 now U.S. Pat. No. 4,063,218.

This invention relates to aviation equipment and, in particular, toaircraft take-off and landing systems.

There are known take-off and landing systems comprising differentfunctionally isolated systems making up a take-off and landing system asa whole and performing different functions at successive stages of thetake-off or landing, special mention being deserved by localizer andglide slope transmitter systems indicating the course and glide slope toan aircraft during landing, radio beacon systems, lighting systemsmarking the runway, approach and lead-in lights systems, radio markersystems indicating the moment of an aircraft being overhead the middleand outer marker locators, and, in the Instrument Landing System (ILS),also overhead an additional middle marker locator, various groundcontrolled approach systems, etc. All these systems are based onemployment of electromagnetic radiation of radio-frequency or visiblerange. Specifically, localizer and glide slope systems use radiowaves ofmetric, decimetric, or centimetric wavelengths. Such systems as approachand lead-in lights, as well as runway marking systems are made as visualmeans assisting the pilot to determine the location of his aircraft inspace in relation to the runway. There are also known lighting systemsindicating the glide slope and course of an aircraft. Such systems arefrequently employed for landing aircraft on a carrier deck. Among theseis a landing system made as a mirror indicator and designated as DeckLanding Mirror Sight (DLMS).

Besides, there is a DLPS (Deck Landing Projector Sight) landing systemor the so called projector approach indicator.

Despite the tremendous difference in the structural principle, purposeand design, all these systems are common in that they employelectromagnetic radiation as directed radiation, any scattered radiationbeing regarded as an interfering noise.

Enhancing flight safety is currently considered one of the major trendsin the progress of aviation, particularly at the stage of approach forlanding and landing itself.

The solution of the problem will make it possible to introduce morestringent landing minima (altitude of decision taking and runwayvisibility distance). This may result in decrease of aircraft idle timecaused by adverse weather conditions, and higher economic efficiency ofaviation, particularly of civil airlines.

That is why take-off and landing systems are constantly improved, newones are developed and old ones are upgraded to step up theirreliability and service life. Development and improvement of take-offand landing systems are basically characterized by a tendency to upgradethe performances of separate, functionally isolated systems constitutinga take-off and landing system as a whole, as well as to provide newsystems permitting automatic approach and landing until aircrafttouch-down and landing run. Besides, a plurality of various auxiliaryand additional systems have been and are being developed to serve asduplicates of those in operation at present or to perform auxiliaryfunctions assisting the pilot to take off or land. Even the advent ofnew sources of electromagnetic radiation, exhibiting novel properties,gives rise to development of systems duplicating the existingfunctionally isolated systems.

Thus, the invention of lasers resulted in development of a number ofvisual auxiliary systems assisting the pilot to determine the directionto the runway. In particular, there is a navigational system accordingto U.S. Pat. No. 3,874,968, which is structurally made as three rows ofreflecting mirrors positioned along straight lines directed to therunway, laser beams being reflected therefrom, comprising lasingsources, vertical beam oscillating means and a beam visibility limitingmeans. Such a system produces an effect of a beam travelling in thedirection of the runway and helps the pilot to find that direction. Thewidth of the approach zone is limited by the beams reflected from thescreens placed to the left and to the right of the runway and narrows asan aircraft approaches the runway.

However, as it was pointed out at the 7th Aeronavigational Conferenceheld in Montreal in April, 1972, none of the existing landing systems,including the international Instrument Landing System (ILS), will beable to meet, in the near future, the requirements imposed upon landingsystems, since transition to more rigid landing minima calls for betteraccuracy and a wider sphere of functional capabilities as compared tothe ILS system. The advent of new types of aircraft is also to be takeninto consideration.

The 7th Aeronavigational Conference considered the present situation andpromoted an ICAO programme project to develop a new landing approachsystem. Such a system is to possess much greater capabilities and,primarily, high-degree accuracy. Suffice it to say that the permissiblealtitude error at the runway threshold should not exceed 1.2 m anddiminish till the beginning of levelling-off directly prior to landing.Besides, the system is to provide for control along the landing path,thereby offering an acceptable accuracy of landing.

This decision of the 7th Aeronavigational Conference derives from thefact that the systems in service feature a number of fundamentaldisadvantages, their low sensitivity being among the most serious onesand, consequently, low accuracy of aircraft flying and a narrow scope offunctions. Though the accuracy of localizer and glide slope transmittersystems is more often than not satisfactory and outperforms similarpurpose lighting systems in accuracy many times over, they make flyingof an aircraft difficult since there is not reliable visual informationas to the spatial attitude of an aircraft. Some steps have been taken,however, in the last years. In particular, television systems areemployed permitting the pilot to see the runway in low-visibilityconditions or systems projecting the instrument information onto thewindscreen, etc.

A holographic landing indicator (cf. U.S. Pat. No. 3,583,784) may betaken as an example, whereon an image of the runway is displayed beforethe pilot corresponding to the actual attitude of the aircraft inrelation to the runway at a given moment.

The appearance of a great number of various functionally isolatedsystems constituting a take-off and landing system as a whole resultedin development of a whole set of diverse instruments mounted aboard theaircraft. The pilot should watch the readings of a plurality ofinstruments during landing and observe the situation outside theaircraft. This is the cause of a high psychological stress, makespilotage difficult and gives rise to additional accident cause factors,since transition from instrument to visual flying and observation of theoutside space demands a period of 3-5 sec for visual accomodation andground objects identification.

It should be emphasized that in developing various functionally isolatedsystems comprising a take-off and landing system as a whole, emphasis islaid on the development of systems for aircraft landing. This is due tothe fact that the process of landing is no doubt more complicated andthe number of flight accidents and air crashes is decidedly higherduring landing than during take-off. The advent of high-speed and,particularly, supersonic aircraft, however, has posed the problem oftake-off safety, especially in difficult weather conditions.

Availability of diversified take-off and landing systems with aplurality of various functionally isolated systems resulted inevolvement of several landing techniques. The number of take-off methodsis much fewer.

The method of aircraft take-off and landing depends on the nature of atake-off and landing system. Landing technique comprises a number ofsuccessive operations and consists in bringing an aircraft within thecoverage of an airfield take-off and landing system, aircraft descentalong an estimated landing path, flaring out, landing and ground run.

In case of the take-off and landing system of an airfield comprises alocalizer and glide slope transmitter system, the landing process properstarts with the moment the aircraft on-board equipment captures thelocalizer and glide slope transmitter landing system.

An estimated landing path of localizer and glide slope transmittersystems is the line of intersection of the course plane and the glideslope plane of an aircraft produced by a localizer and a glide slopetransmitter, respectively. These planes are usually equisignal zones or,in some instances, zones of modulation frequencies minimum radiation.Aircraft deviation from the equisignal zone of a localizer is determinedby the localizer receiver, whereas deviation from the equisignal zone ofa glide slope transmitter is determined with the help of the glide slopereceiver. Basically, two radio beacon instrument landing systems arecurrently used in civil aviation: the international ILS system(Instrument Landing System) and a landing system employed by airfieldsin the Soviet Union (CII50), the difference between these two systemsbeing the nature of beacon radiation. In case an airfield is notequipped with a localizer and glide slope transmitter system, anaircraft moves in the glide slope plane by determining the distance tothe runway threshold and its altitude, as well as the moment of flyingoverhead the radio markers. The course is controlled by tracking homingbeacons and by a magnetic compass.

As the aircraft approaches the runway threshold, it is flown, beginningfrom the decision height, visually by landmarks and by night with thehelp of lighting aids arranged on the ground on the runway along itsedges and at its approaches. The aircraft is usually flared out manuallywith visual orientation by references on the runway. Then, the aircrafttouches down and performs the landing run.

In the case of automatic landing, the whole process of landing to theend of the ground run is performed fully automatically. The existingautomatic landing systems are, however, far from being perfect and donot satisfy the requirements imposed thereon.

The take-off technique consists in running, separation and climbing, andis currently performed manually, because no take-off systems have beendeveloped so far, except for lighting aids and runway lights.

Carrier landing systems are, as a rule, of a combined type and compriselocalizer and glide slope transmitter systems and light course and glideslope indicator systems for greater landing reliability. Besides,various additional monitoring and auxiliary systems are employed toincrease landing safety.

Among carrier radio landing systems are, for example, the A-Sean systemdeveloped by the Flazesean company, the AN/SN-42 system operating inthree modes: command, semi-automatic and fully automatic, as well as theACLS system (All-Weather Carrier Landing System) and the like.

Modern carrier landing systems operate, as a rule, automatically both atthe stage of bringing an aircraft to an estimated landing path and atthe stage of landing proper until the aircraft touches the landing deck.Visual systems are employed for monitoring and for manual landing incase of automatic equipment failure.

Development of take-off and landing systems composed of variousfunctionally isolated systems performing a variety of functions in theprocess of aircraft take-off and landing is not the result of a unifiedeffort to solve the problem of safe and reliable aircraft landing, but aproduct of lengthy evolution, the systems being gradually improved,supplemented by others, duplicated, etc. The result of that prolongedprocess of improvement has been that information on the spatial attitudeof an aircraft, supplied by diverse isolated systems, comprises avariety of basically different signals, like, for example, deflectionsof pointers or bars of instruments of localizer and glide slopetransmitter systems, light signals of light systems, in particular,approach and lead-in lights systems, audible signals indicating flightoverhead radio markers, etc. The inflow of a great number offunctionally isolated systems has been brought about by a striving tomake up to shortcomings of some component systems by using others. Thus,for example, light localizer - GS systems complement radio localizer -GS systems to make up for their most serious drawback consisting in thatvisual observation of the estimated landing path is impossible.

Practically all existing take-off and landing systems are deficient inthat they do not produce clearly marked spatial runway limits, providingno extension to the runway which would make landing so much easier.Lighting aids marking runway boundaries, as well as approach and lead-inlights serve the purpose to a certain degree, but such equipment ispositioned on an airfield in a plane different from the glide slopeplane. This demands great skill of spatial orientation of the pilot.Systems producing light glide slopes based on light beam dynamicsprovide indistinct borders of the glide slope plane, since it is markedby spotlight beams and due to their characteristics, particularly totheir great divergence, the borders are blurred.

The list of similar drawbacks of conventional take-off and landingsystems may be continued, but it will be stopped here, since many of thedrawbacks are fully evident as they were emphasized in the documents ofthe 7th Aeronavigational Conference resulting in the promotion of adraft ICAO program to develop new landing systems.

The problem of developing a take-off and landing system complying withthe requirements of modern aviation and its future progress may besolved only comprehensively and is to employ new principles of systemdesign different from the traditional ones, since they have alreadyexhausted their potentialities. It should also be taken intoconsideration that a pilot is to be provided with reliable informationon the aircraft's spatial attitude on its take-off path and itsdeviations from the estimated take-off path.

It is an object of this invention to provide a take-off and landingsystem ensuring the entire process of landing of an aircraft from themoment it comes to the landing course to the end of the landing run andthe process of take-off of an aircraft from the moment it starts itstake-off run till reaching the safe altitude.

Another object of this invention is to provide a take-off and landingsystem ensuring high accuracy of aircraft take-off and landing,exceeding the accuracy of all currently used take-off and landingsystems.

Yet another object of this invention is to provide a take-off andlanding system which can be made both instrumental and visual withproper selection of a wavelength of electromagnetic radiation.

Still another object of the invention is to provide a visual take-offand landing system ensuring the process of aircraft take-off and landingwith an accuracy no less than that of any modern instrumental take-offand landing systems.

A further object of this invention is to provide a landing systemensuring high accuracy of aircraft landing on the landing deck of acarrier ship.

A still further object of this invention is to provide a landing systemensuring high accuracy of aircraft landing.

Another object of this invention is to provide a take-off systemensuring high accuracy of aircraft take-off.

Yet another object of this invention is to provide a take-off andlanding system featuring high accuracy of aircraft take-off and landingin any weather.

Still another object of this invention is to provide a landing systemindicating an assigned distance to the beginning of a runway.

A further object of this invention is to provide a landing systemindicating an assigned speed of aircraft's flight along the estimatedlanding path.

A still further object of this invention it to provide a take-off andlanding system indicating the boundaries of a runway.

Another object of this invention is to provide a take-off and landingsystem ensuring determination of the magnitude and direction of theaircraft's bank in the course of take-off and landing.

Yet another object of this invention is to provide a landing systemensuring aircraft landing along a curved or broken landing path.

A further object of this invention is to provide a fundamentally newmethod of aircraft take-off and landing, ensuring high accuracy take-offand landing of an aircraft through the use of the proposed take-off andlanding system, said method remaining the consistent at all stages oftake-off and landing.

A still further object of this invention is to provide a fundamentallynew method of determining the course and glide slope of a take-off orlanding path.

Another object of this invention is to provide a fundamentally newmethod of determining the limits of a take-off or landing corridorduring aircraft take-off and landing.

Yet another object of this invention is to provide a new method ofdetermining the boundaries of a runway.

Still another object of this invention is to provide a new method ofdetermining the assigned range to a runway in the course of aircraftlanding.

A further object of this invention is to provide a new method ofdetermining the aircraft flare initiation point during landing.

Another object of this invention is to provide a new method ofdetermining the aircraft's bank during take-off or landing.

Yet another object of this invention it to provide a fundamentally newmethod of landing an aircraft along a curved or broken path.

Still another object of this invention is to provide a fundamentally newmethod of determining motions of a ship landing deck during aircraftlanding.

Still another object of this invention it to provide a basically newmethod of determining the assigned speed of the aircraft's flight alongthe estimated landing path.

And, finally, another object of this invention is to provide afundamentally new method being the same in instrumental and visualtake-off or landing of an aircraft.

These and other objects are achieved by that an aircraft take-off andlanding system is made as directed extended references made up ofelectromagnetic pencil beams with a divergence no greater than 5° and awavelength lying within atmospheric windows, one or several sources ofsaid beams being positioned on a flight platform. These beams areperceived on board an aircraft, when it is outside the direct radiationzone, owing to scattering of the electromagnetic radiation, producing abeam, on air molecules and atmospheric aerosols, and produce a symbolacquiring a specified configuration in case the aircraft is on anestimated take-off or landing path.

Some of the beams, besides producing a symbol of the estimated take-offor landing path, produce additional symbols acquiring a specifiedconfiguration when an aircraft reaches an assigned range or the surfaceof the take-off and landing platform. All symbols produced by the beamsof various sources are basically alike and ensure determination, besidesaircraft's deviations from the estimated take-off or landing path, ofthe aircraft's bank, the assigned range to the take-off and landingplatform, as well as deviations of the aircraft's speed from theassigned speed of movement along the estimated take-off or landing path.

These objects are achieved by providing a new method of aircrafttake-off and landing, consisting in that an aircraft is piloted along anestimated take-off or landing path by maintaining the specified symbolconfiguration, and all aircraft's deviations from said path may bedetermined by distortions of said symbol configuration. The take-off andlanding method is consistent at all stages of take-off or landing andensures successive execution of all steps during take-off or landing bydistortions of the specified symbol configuration.

The following terms will be used henceforth in the specification toavoid ambiguity and for the sake of simplicity.

Take-off and landing platform is a prepared site for aircraft take-offor landing, positioned on the ground or aboard a ship, or forming partof a water surface. In a specific case the take-off and landing platformmay be a runway on a ground airfield, as well as a take-off or landingdeck of a ship. The take-off and landing platform is a part of a flightplatform.

Flight platform is an area including the take-off and landing platform,as well as adjacent take-off termination areas and side safety strips. Aflight platform is a part of an airfield. In a specific case, the flightplatform is a flight strip of a ground airfield with a width of no lessthan 150 m to each side of the runway center line or take-offtermination area.

Directed extended reference is a system of material points or bodiescontrasting against the background of the environment and organized asextended directed plane or 3-D configurations of small cross dimensions.Examples of directed extended references can be found in markings of ahighway or a runway, curb stones running along the edges of a highway,etc. Directed extended references may be made as a system of discreteluminous points, such as lights indicating the side boundaries of arunway or its center line, etc.

Electromagnetic pencil beams with a divergence no greater than 5° andenergy contrast in the selected wavelength against the background of theenvironment are employed in the proposed invention as directed extendedreferences. The cross section of a beam should be such that, when anaircraft is on the estimated take-off or landing path, it is perceivedat an angle of no more than 10° to provide for the required accuracy andsensitivity of the system. The best results, however, can be obtained ifthe beam cross section permit its perception at an angle of no more than1-2°.

The energy contrast derives from the fact that the energy density ofscattered electromagnetic radiation, resulting from propagation ofdirect electromagnetic radiation in the atmosphere, producing the beamexceeds the energy density of the background and is achieved by theappropriate power of direct electromagnetic radiation producing thebeam.

The wavelength of electromagnetic radiation is to be selected so that itis within so-called atmospheric windows, that is, it corresponds to theconditions of minimum absorption by air molecules and atmosphericaerosols. Under these conditions, direct radiation is attenuated andalmost completely transformed into scattered radiation. Scatteringoccurs on air molecules, so-called Rayleigh scattering, as well as onaerosols present in the atmosphere, so-called Mie scattering. Due toscattering, the energy contrast of the beam becomes apparent against thebackground of the environment, and this scattered radiation may bedetected by a receiver, if it deviates sidewise from the beam.

If the wavelength of electromagnetic radiation is selected within thevisible range of electromagnetic radiation, the beam becomes visible.Therefore, the receiver may be a human eye and the take-off and landingsystem using such beams becomes a visual system.

Glide slope is a path of an aircraft take-off or landing during take-offor approach for landing. The notion "glide slope" in this case, unlikethe commonly accepted term, is extended to include a take-off path forthe sake of unification of terminology. Words "take-off" or "landing"are added to make clear what glide slope is meant, e.g., "aircrafttake-off glide slope".

Estimated glide slope is a glide slope of a specific airfield ensuringthe required obstacle clearance limit.

Glide slope plane is a plane orthogonal to the course plane andcomprising the estimated glide slope.

Source of electromagnetic radiation is a means for emitting orreflecting an electromagnetic beam, made as a mirror, reflectingsurface, aerial array, etc, or a generator, as in the case of lasers orspotlights.

Electromagnetic pencil beams are beams with a divergence no greater than5°. The best results, however, can be obtained with a beam divergence nogreater than 5'-10'. The extreme minimum divergence of anelectromagnetic beam equals the natural diffraction divergence, itsmagnitude being proportional to the wavelength of radiation andinversely proportional to the outlet apperture of a generator orradiator. When an electromagnetic beam does not conform to theserequirements, the sources of electromagnetic radiation are provided withcollimators. Beams may be collimated by all known methods and with thehelp of various means, including lenses, mirrors, reflectors orcavities, as well as in the electromagnetic generator itself, as in thecase of a laser.

Beginning of the take-off and landing platform is the limit of theplatform wherefrom an aircraft starts its take-off or landing run. It isoften termed "edge" or "threshold".

End of the take-off and landing platform is its limit opposite to thebeginning, that is the limit of the take-off and landing platform towardwhich an aircraft moves during its take-off or landing run.

The invention will now be described in greater detail with reference tospecific embodiments thereof, taken in conjunction with the accompanyingdrawings, wherein:

FIG. 1 shows an embodiment of the take-off and landing system with onesource of electromagnetic radiation, positioned on a flight platform, inaccordance with the invention;

FIG. 2 shows an embodiment of the take-off and landing system with onesource of electromagnetic radiation, positioned on the center line of atake-off and landing platform, its beam being oriented in a courseplane, in accordance with the invention;

FIG. 3 is a table of distortions of configuration of the symbol producedby the beam of the source of electromagnetic radiation of the take-offand landing system of FIG. 1 for various aircraft attitudes in relationto an estimated take-off or landing path, in accordance with theinvention;

FIG. 4 shows an embodiment of the take-off and landing system with onesource of electromagnetic radiation, positioned on one side of thecenter line of a take-off and landing platform, in accordance with theinvention;

FIG. 5 shows an embodiment of the take-off and landing system with twosources of electromagnetic radiation, one being positioned on the centerline of a take-off and landing platform and its beam being oriented inthe course plane, and the other being positioned on one side of thecenter line and its beam being oriented in the glide slope plane, inaccordance with the invention;

FIG. 6 shows an embodiment of the take-off and landing platform with twosources of electromagnetic radiation, one of these sources beingpositioned on the center line of a take-off and landing platform and theother, on one side of its center line on the side boundary of thisplatform, in accordance with the invention;

FIG. 7 is a table of distortions of a specified configuration of thesymbol produced by the beams of the sources of electromagnetic radiationof the take-off and landing system of FIGS. 5 and 6 for various aircraftattitudes in relation to an estimated take-off or landing path, inaccordance with the invention;

FIG. 8 shows an embodiment of the take-off and landing system with twosources of electromagnetic radiation, positioned on the center line of atake-off and landing platform, their beams being oriented in the courseplane, in accordance with the invention;

FIG. 9 is a table of distortions of a specified configuration of thesymbol produced by the beams of the sources of electromagnetic radiationof the take-off and landing system of FIG. 8 for various aircraftattitudes in relation to the take-off or landing path, in accordancewith the invention;

FIG. 10 shows an embodiment of the take-off and landing system with onemain pair of sources of electromagnetic radiation, positioned on atake-off and landing platform, their beams being oriented in a commonglide slope plane, in accordance with the invention;

FIG. 11 shows an embodiment of the take-off and landing system with onemain pair of sources of electromagnetic radiation, positioned on theside boundaries of a take-off and landing platform, in accordance withthe invention;

FIG. 12 is a table of distortions of a specified configuration of thesymbol produced by the beams of the sources of electromagnetic radiationof the take-off and landing system of FIGS. 10 and 11 for variousaircraft attitudes in relation to an estimated take-off or landing path,in accordance with the invention;

FIG. 13 shows an embodiment of the take-off and landing system with twopairs of sources of electromagnetic radiation, positioned on a take-offand landing platform on either side of its center line, their beamsbeing oriented in pairs in glide slope planes different for each pair,in accordance with the invention;

FIG. 14 shows an embodiment of the take-off and landing system with twopairs of sources of electromagnetic radiation, positioned on the sideboundaries of a take-off and landing platform, two on each side, inaccordance with the invention;

FIG. 15 is a table of distortions of a specified configuration of thesymbol produced by the beams of the sources of electromagnetic radiationof the take-off and landing system of FIGS. 13 and 14 for variousaircraft attitudes in relation to an estimated take-off or landing path,in accordance with the invention;

FIG. 16 shows an embodiment of the take-off and landing system withthree pairs of sources of electromagnetic radiation, positioned on atake-off and landing platform on either side of its center line, theirbeams being oriented in pairs in glide slope planes different for eachpair, in accordance with the invention;

FIG. 17 shows an embodiment of the take-off and landing system withthree pairs of sources of electromagnetic radiation, positioned on theside boundaries of a take-off and landing platform, three on each side,in accordance with the invention;

FIG. 18 is a table of distortions of a specified configuration of thesymbol produced by the beams of the sources of electromagnetic radiationof the take-off and landing system of FIGS. 16 and 17 for variousaircraft attitudes in relation to an estimated take-off or landing path,in accordance with the invention;

FIG. 19 shows an embodiment of the take-off and landing system with themain pair of sources of electromagnetic radiation positioned on eitherside of the center line of a take-off and landing platform and a thirdsource positioned on its center line, in accordance with the invention;

FIG. 20 shows an embodiment of the take-off and landing system with twopairs of sources of electromagnetic radiation, positioned in pairs oneither side of the center line of a take-off and landing platform and afifth source positioned on its center line, in accordance with theinvention;

FIG. 21 shows an embodiment of the take-off and landing system withthree sources of electromagnetic radiation, two of these sources beingarranged in a pair and positioned on the opposite side boundaries of atake-off and landing platform, their beams being oriented in a commonglide slope plane, and the third being positioned below the glide slopeplane, in accordance with the invention;

FIG. 22 is a table of distortions of a specified configuration of thesymbol produced by the beams of the sources of electromagnetic radiationof the take-off and landing system of FIG. 21 for various aircraftattitudes in relation to an estimated take-off or landing path, inaccordance with the invention;

FIG. 23 shows an embodiment of the take-off and landing system with foursources of electromagnetic radiation, two of these sources beingarranged in a pair and positioned on the opposite side boundaries of atake-off and landing platform, their beams being oriented in a commonglide slope plane, whereas two other sources are positioned on thecenter line of the take-off and landing platform, their beams beingarranged so that one in below and the other above the glide slope plane,in accordance with the invention;

FIG. 24 shows an embodiment of the take-off and landing system with apair of additional sources of electromagnetic radiation, positioned on aflight platform in the immediate vicinity of the end of the take-off andlanding platform (sources of electromagnetic radiation, comprising acourse and glide slope group are not shown), in accordance with theinvention;

FIG. 25 is a table of distortions of a specified configuration of thesymbol produced by the beams of one additional pair of sources ofelectromagnetic radiation of the take-off and landing system of FIG. 24for various aircraft attitudes in relation to the surface of thetake-off and landing platform, in accordance with the invention;

FIG. 26 shows an embodiment of the take-off and landing system with anadditional source of electromagnetic radiation, positioned on a flightplatform in the immediate vicinity of the end of the take-off andlanding platform (sources of electromagnetic radiation, comprising acourse and glide slope group are not shown), in accordance with theinvention;

FIG. 27 is a table of distortions of a specified configuration of thesymbol produced by the beam of one additional source of electromagneticradiation of the take-off and landing system of FIG. 26 for variousaircraft attitudes in relation to the surface of the take-off andlanding platform, in accordance with the invention;

FIG. 28 shows an embodiment of the take-off and landing system with apair of additional sources and one more additional source ofelectromagnetic radiation, positioned on a flight platform in theimmediate vicinity of the end of the take-off and landing platform(sources of electromagnetic radiation, comprising a course and glideslope group are not shown), in accordance with the invention;

FIG. 29 is a table of distortions of a specified configuration of thesymbol produced by the beams of the additional sources ofelectromagnetic radiation of the take-off and landing system of FIG. 28for various aircraft attitudes in relation to the surface of thetake-off and landing platform, in accordance with the invention;

FIG. 30 shows an embodiment of the take-off and landing system with apair of second additional asymmetrically arranged sources ofelectromagnetic radiation, positioned on a flight platform, their beamsindicating a marker point (sources of electromagnetic radiation,comprising a course and glide slope group and a landing lights group arenot shown), in accordance with the invention;

FIG. 31 shows an embodiment of the take-off and landing system similarto that of FIG. 31, with the sources of electromagnetic radiation beingsymmetrically arranged, in accordance with the invention;

FIG. 32 is a table of distortions of a specified configuration of thesymbol produced by the beams of the second additional sources ofelectromagnetic radiation of the take-off and landing system of FIGS. 30and 31 for various aircraft attitudes in relation to the marker point,in case the beams of these sources do not intersect the glide slopeplane, in accordance with the invention;

FIG. 33 is a table of distortions of a specified configuration of thesymbol produced by the beams of the second additional sources ofelectromagnetic radiation of the take-off and landing system of FIGS. 30and 31 for various aircraft attitudes in relation to the marker point,in case these beams intersect with the glide slope plane, in accordancewith the invention;

FIG. 34 shows an embodiment of the take-off and landing system in itslanding version, comprising all three groups of sources ofelectromagnetic radiation, a course and glide slope group, a landinglights group and a marker group, in accordance with the invention;

FIG. 35 shows an embodiment of the take-off and landing system in itslanding version, comprising two groups of sources of electromagneticradiation, a course and glide slope group and a landing lights group, inaccordance with the invention;

FIG. 36 shows an embodiment of the landing system with three sources ofelectromagnetic radiation, positioned at the beginning of a take-off andlanding platform and three auxiliary sources of electromagneticradiation, positioned before the take-off and landing platform, inaccordance with the invention;

FIG. 37 shows an embodiment of the take-off and landing systemcomprising one source of electromagnetic radiation, positioned on acarrier landing deck in the immediate vicinity of an estimated touchdownzone, in accordance with the invention;

FIG. 38 shows an embodiment of the take-off and landing systemcomprising two sources of electromagnetic radiation, one of thesesources being positioned on a carrier landing deck in the immediatevicinity of an estimated touchdown zone and the second one, on the sternedge, in accordance with the invention;

FIG. 39 shows an embodiment of the take-off and landing systemcomprising two sources of electromagnetic radiation, positioned on acarrier landing deck on its side boundaries, symmetrically about itscenter line, in the immediate vicinity of an estimated touchdown zone,in accordance with the invention;

FIG. 40 shows an embodiment of the take-off and landing systemcomprising three pairs of sources of electromagnetic radiation,positioned on a carrier landing deck, on its side boundaries, in pairssymmetrically about its center line, in accordance with the invention;

FIG. 41 shows an embodiment of the take-off and landing systemcomprising a pair of sources of electromagnetic radiation, positioned ona carrier landing deck in the immediate vicinity of an estimatedtouchdown zone and a third source positioned on the stern edge, inaccordance with the invention;

FIG. 42 shows an embodiment of the take-off and landing systemcomprising all three groups of sources of electromagnetic radiationpositioned on a carrier landing deck, in accordance with the invention;

FIG. 43 shows an embodiment of the take-off and landing systemcomprising two pairs of sources of electromagnetic radiation, providedwith a beam turning means, in accordance with the invention;

FIG. 44 shows an embodiment of the take-off and landing systemcomprising three sources of electromagnetic radiation provided with abeam turning means, in accordance with the invention;

FIG. 45 shows an embodiment of the take-off and landing systemcomprising one source of electromagnetic radiation, positioned on aflight platform and provided with a beam rotating means, in accordancewith the invention;

FIG. 46 shows an embodiment of the take-off and landing systemcomprising one source of electromagnetic radiation, positioned on thecenter line of a take-off and landing platform and provided with a beamrotating means, in accordance with the invention;

FIG. 47 is a table of distortions of a specified configuration of thesymbol produced by the beam of the source of electromagnetic radiationof the take-off and landing system of FIG. 46 for various aircraftattitudes in relation to an estimated take-off or landing path, inaccordance with the invention;

FIG. 48 shows an embodiment of the take-off and landing system in itstake-off version, comprising two sources of electromagnetic radiation,provided with beam rotating means, one of these sources being placed inthe immediate vicinity of the lift-off point and the other on a flightplatform in the immediate vicinity of the end of the take-off andlanding platform, in accordance with the invention;

FIG. 49 shows an embodiment of the take-off and landing system in itslanding version, comprising two sources of electromagnetic radiation,provided with beam rotating means, one of these sources being placed atthe beginning of a take-off and landing platform and the other, on aflight platform in the immediate vicinity of the end of the take-off andlanding platform, in accordance with the invention;

FIG. 50 shows an embodiment of the take-off and landing systemcomprising three sources of electromagnetic radiation, provided withbeam rotating means, in accordance with the invention;

FIG. 51 is a picture of the take-off and landing system of FIG. 21;

FIG. 52 is a picture of the symbol produced by the sources ofelectromagnetic radiation positioned as shown in FIG. 34, in accordancewith the invention.

The proposed aircraft take-off and landing system is made up of directedextended references, the number whereof may vary and is dependent uponthe functional requirements imposed on the system. Pencil beams ofelectromagnetic radiation with a small divergence and a wavelength lyingwithin atmospheric windows are employed as such directed extendedreferences. The wavelengths of electromagnetic radiation are selected tosuit the purpose of a system and the requirements imposed thereupon.Thus, for example, electromagnetic beams of the superhigh frequency orextremely high-frequency band are employed as directed extendedreferences for arrangement of instrumental nonvisual systems, thesources of electromagnetic radiation being pencil-beam aerials orlasers. Besides, electromagnetic radiation with a wavelength in the nearor far infrared region may be employed, as well as in the γ-range ofradiation spectrum. Thus, for visual take-off and landing systems,electromagnetic pencil beams with a small divergence in the optical bandare employed as directed extended references, the sources ofelectromagnetic radiation being, for example, projectors or lasers.

In selection of a wavelength of electromagnetic radiation it isextremely important that the selected wavelength should correspond to anatmospheric window. Such a selection permits substantial increase in theefficiency of the take-off and landing system operation at the expenseof reduced absorption of electromagnetic energy by the atmosphere. It isa matter of common knowledge that the atmosphere has a number of windowsin various frequency bands of the electromagnetic radiation spectrum.Thus, for example, there are several atmospheric windows within thecentimetric and millimetric band of the electromagnetic radiationspectrum with a wavelength of 3,000-3,500 mu, as well as 1,000-2,000 mu,wherein the absorption of energy by molecules of the atmosphere and ofwater aerosols is insignificant in relation to the total amount ofscattered energy.

Another example is several atmospheric windows in the far infraredregion of the electromagnetic radiation spectrum with a wave band of 10to 15 mu, as well as several atmospheric windows in the near infraredregion from 1 to 6 mu. Some lasers operate on the wavelengthscorresponding to these atmospheric windows, e.g. CO₂ molecular lasersgenerating electromagnetic radiation on a wavelength of 10.6 mu or COmolecular lasers with a wavelength of 5.1 mu, which may be also used assources of electromagnetic radiation to produce directed extendedreferences.

There is a wide atmospheric window within a wavelength range from 0.2 to0.8-1 mu, wherein the absorption amounts to no more than 8-12 percent ofthe total attenuation of electromagnetic radiation. This is theso-called optical band. Various projector systems, as well as lasers,generating electromagnetic radiation of a certain colour may be employedas sources of electromagnetic radiation to produce directed extendedreferences in this band.

And finally, there are several atmospheric windows, wherein absorptionis minimum, in the ultraviolet region of the electromagnetic radiationspectrum with a wavelength from 0.32 to 0.4 mu, as well as in the regionof γ-radiation possessing a high penetrating power.

In case monochromatic electromagnetic radiation is employed to producedirected extended references, proper consideration should be given, inselection of a wavelength of this radiation, to the fine structure ofatmospheric windows, since it may turn out that the selected wavelengthof electromagnetic radiation does not fit the atmospheric window andelectromagnetic radiation on the selected wavelength may be subjected tostrong atmospheric absorption. If electromagnetic radiation falls in thestrong absorption band, that is out of the atmospheric window, itswavelength should be somewhat altered so that minimum atmosphericabsorption of electromagnetic radiation can be achieved. Examples ofmonochromatic radiation sources are sources of radio-frequencyradiation, as well as many lasers, e.g. a helium-neon gas lasergenerating at one frequency with a wavelength of 0.6328 mu.

Some sources of electromagnetic radiation generate on severalwavelengths, part of them falling within atmospheric windows, otherslying outside in wavelength regions wherein electromagnetic radiation isabsorbed by the atmosphere. An example of sources generatingelectromagnetic radiation in a multitude of wavelengths simultaneouslyare projectors producing white light, as well as some lasers.

In some cases, directed extended references may be produced by acombination of several wavelengths of electromagnetic radiation to suitthe requirements set to the take-off and landing system. Thus, forexample, a visual take-off and landing system intended for reliableoperation in dense fog may employ a combination of infraredelectromagnetic radiation, e.g. radiation with a wavelength of 10.6 muor 5.1 mu, with electromagnetic optical radiation, e.g. with awavelength of 0.6328 mu produced by a helium-neon gas laser or 0.57 muproduced by an argon laser.

Such a combination of electromagnetic radiation with differentwavelengths makes it possible to burn through a channel in the fog bymeans of infrared radiation and send optical radiation along thischannel to ensure visual observation of directed extended references.

Directed extended references may be observed or registered byinstruments owing to the energy contrast of a directed extendedreference against the background of the environment. The beam is asthough radiating or glowing. As it has already been mentioned, suchradiation or glow is due to scattering of electromagnetic energy onmolecules and aerosols of the atmosphere and consists in chaoticchanging of direction of electromagnetic radiation propagation whenpassing through the atmosphere. The beam, in this case, functions as anenergy carrier. When an aircraft deviates laterally, the beam is seen asa straight line, its inclination with respect to the course planeindicating the vertical attitude being dependent on the attitude of theaircraft in relation to the beam. The straight line produces a symbol.When there are several beams, the symbol comprises several rectilinearelements, their relative position being an unambiguous indication of thespatial aircraft attitude. When an aircraft is on an estimated take-offor landing path, the symbol produced by the beams acquires aconfiguration depending on the number of electromagnetic beams and theirrelative positions. Optimum arrangement of the electromagnetic sourceson the take-off and landing platform produces a symbol formed by theirbeams, characterized by a simple and easy to remember configuration.

The symbol is, therefore, a means to perform aircraft take-off andlanding, the degree of the symbol's distortion being a measure of theaircraft's deviation from the estimated take-off or landing path,whereas directed extended references produced by electromagnetic beamsserve to form this symbol as an instrumental means.

As has already been mentioned, directed extended references are producedby the beams of electromagnetic radiation generated by sources made upof various means, such as, for example, reflecting surfaces, mirrors,aerial arrays or generators proper, like projectors or lasers.

The generator producing electromagnetic radiation may be placed directlyon the flight or take-off and landing platform at the point of origin ofa directed extended reference or any other point of the flight platform.In this case, the beam coming out of the generator falls upon areflecting surface, then, after being reflected therefrom, is directedinto the space performing the function of a directed extended reference.

Different sources are employed depending on the wavelength ofelectromagnetic radiation. Thus, as has been already pointed out,pencil-beam aerials with a beam divergence brought down to 1.5°-2° mayserve as such sources in the superhigh frequency (centimetric) andextremely high-frequency (millimetric) band. In the near and farinfrared band, for example, lasers may be employed as such sources ofelectromagnetic radiation, e.g. CO₂ gas molecular lasers with awavelength of 10.6 mu, CO molecular lasers with a wavelength of 5.1 muor solid-state lasers, e.g. neodymiumdoped glass lasers with awavelength of 1.06 mu. Gas molecular lasers are characterized by highefficiency reaching 40 percent.

Sources of electromagnetic radiation in the optical band may beprojectors radiating white light or provided with filters cutting out acertain part of the spectrum, as well as lasers. Laser sources may be,for example, argon lasers generating green light at some lines, kryptonlasers generating red light, as well as forementioned helium neonlasers. In the γ-band, traditional sources of gamma rays may beemployed, e.g. radio-active materials, as well as γ-lasers beingdeveloped at present.

The forementioned examples demonstrate that the proposed take-off andlanding system can employ, as sources of electromagnetic radiation,various means producing pencil beams, such as radio antennas,projectors, lasers, etc.

Lasers, as sources of electromagnetic radiation, simplify the problem ofproducing electromagnetic pencil beams with a small divergence in manyrespects, since their high directivity is not achieved with the help ofspecial-purpose collimators, e.g. objectives, but is generated insidethe laser cavity. Besides, lasers permit production of beams with a veryhigh electromagnetic energy density, in excess of tens of watts persquare centimeter of the beam area. At present, lasers operate onvarious wavelengths of electromagnetic radiation, from the millimetricwave band to the gamma band.

An embodiment of this invention, wherein lasers are employed as sourcesof electromagnetic radiation in the visual range of the radiationspectrum, is described hereforth for simplicity and ease ofunderstanding. This, however, does not imply that any of the knownsources of electromagnetic radiation, including the forementioned ones,cannot be used separately or in combinations, as will be described inmore detail in what follows.

Sources of electromagnetic radiation are commonly positioned on theflight platform and, in particular, on the take-off and landing platformin places determined by the functional requirements set to the take-offand landing system.

Thus, if a take-off and landing system comprises one source 1 (FIG. 1)of electromagnetic radiation, this source 1 is positioned in any placeof a flight platform 2 comprising a take-off and landing platform 3 andits beam 4 indicates the course and glide slope of a take-off or landingpath W of an aircraft A. Arrow L points out the direction of landing,whereas arrow F denotes the direction of take-off. Letters SS designatethe center line of the take-off and landing platform. The symbolproduced by the beam 4 has a configuration being dependent on theposition of the source 1 of electromagnetic radiation on the flightplatform 2 and distorted in case of any deviations of the aircraft Afrom the estimated take-off or landing path W. The specifiedconfiguration of the symbol and its distortions in case of variousdeviations of the aircraft A from the estimated take-off or landing pathW will be discussed later on with reference to specific embodiments oftake-off and landing systems.

The electromagnetic radiation source 1 (FIG. 2), in accordance with oneof the embodiments of the take-off and landing system, may be positionedon the take-off and landing platform 3 being a part of the flightplatform 2. In case this is the only source 1 of electromagneticradiation, it is advisable to place it on the center line SS of thetake-off and landing platform 3 and orient its beam 4 in space so thatit indicates the course and glide slope of the estimated take-off orlanding path W and lies in the course plane C.

The table (FIG. 3) of distortions of the specified configuration of thesymbol produced by a projection 5 of the electromagnetic beam 4 invarious attitudes of the aircraft A (FIG. 2) in relation to theestimated take-off and landing path W is drawn up to provide anillustrative and simple example of the process of determination by thisdistortion of the direction and degree of deviation of the aircraft Afrom the estimated take-off and landing path W. The projection 5 isformed by projecting the electromagnetic beam 4 in accordance with therules of affine-projective geometry onto a sensitive surface of areceiver of electromagnetic radiation carried by the aircraft A or theretina of the pilot's eyes. The pilot perceives this projection 5 of thebeam 4 against the background of the sky during take-off of the aircraftA and against the background of the flight platform 2 during itslanding.

This table is a schematic of the relative position of the aircraft A andthe projection 5 of the electromagnetic beam 4 producing the symbol inaccordance with the take-off and landing system of FIG. 2. Thisprojection 5 is a straight line. The following notation is used in thetable (FIG. 3).

I--the aircraft is exactly on the glide slope of the estimated take-offor landing path;

II--the aircraft is above the glide slope of the estimated take-off orlanding path;

III--the aircraft is below the glide slope of the estimated take-off orlanding path;

c--the aircraft is exactly on the course of the estimated take-off orlanding path;

l--the aircraft is to the left of the course of the estimated take-offor landing path;

r--the aircraft is to the right of the course of the estimated take-offor landing path.

The distorted configuration of the symbol corresponding to a certainattitude of the aircraft A in relation to the estimated take-off orlanding path W is confined by a square, its coordinates being determinedby a letter designating a certain position of the aircraft A in relationto the course of the estimated take-off or landing path W and a digitdesignating a certain position of the aircraft A in relation to theglide slope of the estimated take-off or landing path. For example, "cI"corresponds to the aircraft A being exactly on the course and glideslope of the estimated take-off or landing path, "rIII" corresponds tothe aircraft A being to the right of the course and below the glideslope of the estimated take-off or landing path.

The symbol produced by the beam 4 (FIG. 3) is the projection 5 of thisbeam looking like a straight line reduced to a dot when the aircraft A(FIG. 2) is on the course and glide slope of the estimated take-off orlanding path W, which corresponds to the cI square of the table ofdistortions of the symbol configuration, that is the aircraft A in thiscase is directly in the electromagnetic beam 4. Such a symbolconfiguration, looking like a dot, is the specified configuration forthe embodiment of the system, wherein the source I of electromagneticradiation is placed as in FIG. 2. The distortion of the specifiedconfiguration of the symbol formed by the projection 5 of theelectromagnetic beam 4 with various deviations of the aircraft A fromthe estimated take-off or landing path W is determined by an inclinationangle φ of the projection 5 of the electromagnetic beam 4 in relation toa vertical 6. In this case, the projection 5 of the beam 4 is as thoughturning about a point 7 designating the point in space whereto the beam4 is directed during take-off of the aircraft A or the point wherefromthe beam 4 leaves the source I of electromagnetic radiation, during itslanding. When the aircraft A takes off, the source I of electromagneticradiation is left behind the aircraft A and cannot be seen by the pilotor detected by the receiver of electromagnetic radiation carried by theaircraft, if it is capable of detecting only "forward" emittedradiation. In case the receiver of electromagnetic radiation is arrangedso that it detects radiation behind the aircraft A, the point 7designates the point wherefrom the beam 4 leaves the source I ofelectromagnetic radiation.

If the aircraft A takes off or lands using the take-off and landingsystem of FIG. 2 and deviates from the glide slope of the estimatedtake-off or landing path W, but staying in the course plane C, thespecified symbol configuration corresponding to the cI square isdistorted and the projection 5 of the electromagnetic beam 4 coincideswith the vertical 6 and is directed downwards from the point 7, whichcorresponds to the cII square, or upwards from this point 7, whichcorresponds to the cIII square. Such distortions of the specified symbolconfiguration correspond to the deviations of the aircraft A from theglide slope of the estimated take-off or landing path W upwards ordownwards respectively. The position of the aircraft is here andhenceforth designated in the table of distortions of the symbolconfiguration as point A.

If the aircraft A deviates from the course of the estimated take-off orlanding path W, the specified symbol configuration is distorted and theprojection 5 of the electromagnetic beam 4, being orthogonal to thevertical 6, is directed to the right of the point 7, which correspondsto the lI square, or to the left of the point 7, which corresponds tothe rI square. Such distortions of the specified symbol configurationcorrespond to the aircraft's deviations from the course of the estimatedtake-off or landing path to the left or to the right respectively. It iseasily comprehended that the projection 5 of the electromagnetic beam 4from the point 7 is always turned in the opposite direction to theposition of the aircraft A deviating from the estimated take-off orlanding path W.

The distortion of the specified symbol configuration is, consequently,an indication of the magnitude and direction of the aircraft's deviationfrom the estimated take-off or landing path W, which is the basis of theproposed take-off and landing system and the fundamental principle ofits structure.

Thus, for example, if the projection 5 of the beam 4 is directeddownward and to the right of the point 7 (the II square in FIG. 3), thismeans that the aircraft A has deviated from the estimated take-off orlanding path W upward and to the left, etc.

This principle will be further used to determine the position of theaircraft A on the estimated take-off and landing path W by thedistortions of the specified configuration of the symbol produced byseveral beams of the sources of electromagnetic radiation.

In another embodiment of the take-off and landing system, the source 1(FIG. 4) of electromagnetic radiation may be positioned on the flightplatform on one side of the center line SS of the take-off and landingplatform 3, which is a part of the flight platform 2, and its beam 4oriented in the glide slope plane G. The source 1 of electromagneticradiation may be placed on one side of the center line SS of thetake-off and landing platform 3, both on this platform 3 (shown in FIG.4 as a solid line) and outside the take-off and landing platform 3(shown in FIG. 4 as a dotted line). The arrow indicates the direction inwhich the source 1 of electromagnetic radiation can be moved over.

Here and henceforth, the beams of the sources of electromagneticradiation placed on one side of the center line SS of the take-off andlanding platform 3 may both be directed parallel to the course plane Cand form a small angle to this plane. This angle may reach severalangular minutes or even amount to 1-5°.

In accordance with the principle used for drawing up the table 3 ofdistortions of the symbol configuration, the specified configuration ofthe symbol produced by the projection of the electromagnetic beam 4positioned as in FIG. 4, when the aircraft A is on the estimatedtake-off or landing path W, looks like a straight line orthogonal to thevertical, that is this straight line is horizontal and the angle φequals 90°.

When the aircraft A deviates from the estimated take-off or landing pathW, the specified configuration of the symbol is distorted and the angleφ is changed, decreasing or increasing according to the direction ofdeviation of the aircraft A from the estimated take-off or landing pathW. The distortions of the configuration of the symbol produced by theelectromagnetic beam 4, with the aircraft A taking off or landing by thetake-off and landing system of FIG. 4, are not shown in figures.

When several sources of electromagnetic radiation are available, thesesources may be divided into groups according to their functions: courseand glide slope group, landing lights group and marker group.

The course and glide slope groups is formed by the sources with beamsindicating the course and glide slope of the estimated take-off orlanding path, producing a symbol and form a take-off or landingcorridor, wherein the estimated take-off or landing path is situated andthe movement of an aircraft is safest. Such a corridor as thoughprolongs the take-off and landing platform by enabling the pilot to flythe aircraft in relation to the limits of the take-off or landingcorridor so that its position corresponds to the optimum position withrespect to the estimated take-off or landing path.

Thus, if the take-off and landing system comprises two sources ofelectromagnetic radiation (FIG. 5) and the first source 1 ofelectromagnetic radiation is placed on the center line SS of thetake-off and landing platform 3, its beam being oriented in the courseplane C, in one of its embodiments a second source 8 of electromagneticradiation may be positioned on one side of the center line SS, its beam9, in combination with the beam 4 of the first source I, defining atake-off or landing corridor K.

The source 8 of electromagnetic radiation may be positioned on one sideof the center line SS of the take-off and landing platform 3 at anyplace on the flight platform 2.

FIG. 5 shows the position of this source 8 on the flight platform 2outside the take-off and landing platform 3 by the dotted line, whereasthe solid line shows a specific embodiment of the take-off and landingsystem, when the second source 8 of electromagnetic radiation ispositioned on the take-off and landing platform 2 to the right of thecourse plane C, if viewed in the direction of landing (arrow L), and itsbeam 9 limits the take-off or landing corridor K from the right and isoriented in the glide slope plane G.

The source 1 of electromagnetic radiation may also be placed at variouspoints on the center line SS of the take-off and landing platform 3,both on and outside the flight platform 2. The dotted line indicates apossible position of this source on the take-off and landing platform,whereas the solid line shows a specific embodiment of the proposedtake-off and landing system, when the source 1 is positioned so that itsbeam 4 is below the glide slope plane G. The arrows indicate possibleshifting of the sources I and 8.

The beam 4 of the source 1 of electromagnetic radiation is below theglide slope plane G and limits said corridor K from below.

It should be kept in mind, however, that when the first source 1 ofelectromagnetic radiation is positioned on the center line SS and thesecond source 8 is aside of this center line SS of the take-off andlanding platform 3, the second source 8 may be placed on the other sideof the center line, whereas the beam 4 of the first source 1 may beabove or below the glide slope plane G or cross this plane G. The source8 (FIG. 6) of electromagnetic radiation may, for example, be positioneddirectly on a side boundary 10 of the take-off and landing platform 3,its beam 9 in this case being an indication of this boundary. Theestimated take-off and landing path W in all these cases is the line ofintersection of the course plane C and the glide slope plane G.

The table of distortions of the specified configuration of the symbol(FIG. 7) produced by the projection 5 of the beam 4 and a projection 11of the electromagnetic beam 9 for various attitudes of the aircraft A(FIGS. 5 and 6) in relation to the estimated take-off or landing path Wis drawn up similarly to the table of FIG. 3. The symbol produced by theprojections 5 and 11 of electromagnetic beams 4 and 9 looks like twostraight lines, the first (5) of them being directed, when the aircraftA (FIGS. 5 and 6) is on the course and glide slope of the estimatedtake-off or landing path W, downward of the point 7 in a directionopposite to the position of the aircraft A and coinciding with thevertical 6, whereas the second projection 11 is directed to the right ofa point 12 in a direction opposite to the position of the aircraft A andorthogonal to the vertical 6. Such a configuration of the symbol is thespecified configuration for the aircraft landing by the take-off andlanding system made as in FIGS. 5 and 6 and corresponds to the cI squareof the table of distortions of the specified symbol configuration (FIG.7).

In the case of take-off according to this take-off and landing system,the projection 11 of the electromagnetic beam 9 will be on the left sidebut still orthogonal to the vertical 6.

The point 12 is similar to the point 7. It should be noted thatadditional points will have absolutely identical functions to those ofpoint 7 and will be determined in similar way.

If the aircraft A, taking off or landing through the use of theembodiment of the take-off and landing system of FIGS. 5 and 6, deviatesfrom the glide slope of the estimated take-off or landing system W, butremains in the course plane C, the specified configuration of the symbolcorresponding to the cI square is distorted. When the aircraft A isabove the glide slope of the estimated take-off and landing path, theprojection 11 of the electromagnetic beam 9 is directed downward and tothe right of the point 12, which corresponds to the cII square, whereas,when the aircraft A is below the glide slope of the estimated take-offand landing path W, it is directed upward and to the right of the point12 (cIII and cIV squares).

The table of FIG. 7 uses, in comparison with that of FIG. 3, thefollowing additional notations:

IV--the aircraft is below the take-off or landing corridor;

t--the aircraft is to the right of the take-off or landing corridor.

The projection 5 of the electromagnetic beam 4, whatever the position ofthe aircraft A in the course plane C, coincides with the vertical 6 andis directed downward of the point 7 when the aircraft is above or belowthe glide slope of the estimated take-off or landing path W (cII andcIII squares), it changes its direction for an opposite one (cIV square)when the aircraft A is below the electromagnetic beam 4 (FIGS. 5 and 6).

The change of the direction of the projection 5 of the electromagneticbeam 4 for an opposite one indicates that the aircraft A is below thetake-off or landing corridor K but still in the course plane C (cIVsquare).

If the aircraft A deviates from the course of the estimated take-off andlanding path W but stays in the glide slope plane G, the specifiedsymbol configuration corresponding to the cI square is distorted. Whenthe aircraft A is to the left of the course of the take-off or landingpath W (II square), the projection 5 of the electromagnetic beam 4 isdirected to the right and downward of the point 7 or to the left anddownward of this point (rI and tI squares) when the aircraft A is to theright of the course of this path W and to the right of the take-off orlanding corridor K.

The projection 11 of the electromagnetic beam 9, whatever the positionof the aircraft A in the glide slope plane G, remains horizontal, thatis orthogonal to the vertical 6, and directed from left to the rightfrom the point 12, when the aircraft is to the left or to the right (LIand rI squares) of the course of the estimated take-off or landing path,and changes its direction for an opposite one, when the aircraft is tothe right of the take-off or landing corridor (tI square).

Such a change of the direction of the projection II of theelectromagnetic beam 9 indicates that the aircraft A is to the right ofthe take-off or landing corridor K (FIGS. 5 and 6) but stays in theglide slope plane G (tI square in FIG. 7).

If the source 8 (FIG. 6) of electromagnetic radiation is positioneddirectly on the side boundary 10 of the take-off and landing platform 3,the change of the direction of the projection II of the beam 9 (FIG. 7)for an opposite one indicates that the aircraft A is to the right ofthis side boundary 10 and outside the take-off and landing platform 3.

If the aircraft A deviated from both the course and glide slope of theestimated take-off or landing path W, the specified symbol configurationis distorted, each position of the aircraft A with respect to the path Whaving a corresponding direction of the projections 5 and 11 of thebeams 4 and 9. The table (FIG. 7) of distortions of the specified symbolconfiguration is a good evidence to this.

Placing the source 8 (FIG. 6) of electromagnetic radiation on the sideboundary 10 of the take-off and landing platform 3 leaves the specifiedsymbol configuration basically unaffected and needs no detaileddescription.

When the aircraft A takes off using the take-off and landing system ofFIGS. 5 and 6, the distortions of the specified symbol configuration aresimilar to those in the table (FIG. 7) with the only difference thatthis symbol is a mirror reflection with respect to the vertical 6passing through the point 7.

The position of the aircraft A in relation to the take-off or landingpath W may be determined by the distortions of the specified symbolconfiguration through the use of the forementioned principle, as well asthe direction of the path correction of the aircraft A.

Another embodiment (FIG. 8) of the take-off and landing system comprisestwo sources of electromagnetic radiation. The first source I ofelectromagnetic radiation is positioned on the center line SS of thetake-off and landing platform 3, its beam 4 being oriented in the courseplane C, and the second source 8 is positioned on the same center lineSS at a certain distance from the first one, its beam 9 defining, incombination with the beam 4, the take-off or landing corridor K. FIG. 8shows a specific embodiment of the take-off and landing system, whereinthe second source 8 is positioned ahead of the first source I, if viewedin the direction of landing (arrow L), its beam being also oriented inthe course plane C, but the two beams do not intersect. The estimatedtake-off or landing path W is situated between these beams 4 and 9, andthey limit the take-off or landing corridor K from below and from above.

The dotted line shows other alternatives of placing the sources I and 8on the center line SS of the take-off and landing platform 3. In thiscase, the source 8 of electromagnetic radiation may also be positionedon the flight platform 2 on the extension of the center line SS of thetake-off and landing platform 3. The arrows indicate possible shifts ofthese sources I and 8.

It should be borne in mind that other alternatives of placing the secondsource 8 on the center line SS of the take-off and landing platform arepossible. The source 8 may be placed behind the first source 1 and thebeams 4 and 9 of the sources I and 8 of electromagnetic radiation mayintersect.

The table of distortions of the specified configuration of the symbol(FIG. 9) produced by the projection 5 of the beam 4 and the projection11 of the beam 9 for various positions of the aircraft A (FIG. 8) withrespect to the estimated take-off or landing path W is drawn upsimilarly to the tables of FIGS. 3 and 5. The specified configuration ofthe symbol for the aircraft's position on the path W is given as beforein the cI square and is made up of two projections 5 and 11 of the beams4 and 9 disposed vertically and extending in opposite directions fromthe points 7 and 12.

If the aircraft A, taking off or landing according to the forementionedembodiment of the take-off and landing system of FIG. 8, deviates fromthe glide slope, but still keeps to the course plane C, the specifiedconfiguration of the symbol is not distorted and it is only when theaircraft comes above or below the take-off or landing corridor K thatone of the projections 5 or 11 of the beams 4 or 9 changes its directionfor an opposite one, coinciding with the vertical 6. This corresponds tocV or cIV squares of the table of distortions of the specified symbolconfiguration (FIG. 9).

The table of FIG. 9 uses the following additional notations incomparison with those of FIGS. 3 and 7:

V--the aircraft is above the take-off or landing corridor.

If the aircraft A deviates from its course, but still keeps on the glideslope of the estimated take-off or landing path W, the specifiedconfiguration of the symbol is distorted and, when the aircraft A is tothe left of the course (lI square), one of the projections 11 isdirected to the right and downward of the point 12 and the secondprojection 5, to the right and upward of the point 7. When the aircraftA is to the right of the course (rI square) the projections 5 and IIoccupy a position symmetrical about the vertical 6.

If the aircraft A is to the left of the course of the estimated take-offor landing path W (this corresponds to l squares of FIG. 9) and deviatesfrom the glide slope of this path W, the symbol configuration isdistorted so that when the aircraft A is above the glide slope angles φ₁and φ₂ become smaller (lII and lV) squares) than angles φ₁ and φ₂ whenthe aircraft is on the glide slope of the path W (lI square), or, incontrast, greater when the aircraft A is below the glide slope of theestimated take-off or landing path W (lIII and lIV squares).

It is easily comprehended that the symbol, in this case, is distorted sothat, when the aircraft A is on the glide slope of the estimated path W,the projections 5 and II of the beams 4 and 9 are symmetrical to eachother with respect to the straight line orthogonal to the vertical 6,and this symmetry is upset when the aircraft A is above or below theglide slope of the estimated path W.

In case the aircraft A is to the right of the course of the path W (thiscorresponds to r squares in FIG. 9) and deviates from the glide slope ofthis path W, the symbol configuration is symmetrical to theforementioned one with respect to the vertical 6.

As before, the position of the aircraft A in relation to the estimatedtake-off or landing path W may be determined through the use of theforementioned principle by the distortions of the specified symbolconfiguration, as well as the direction of its path correction.

If the take-off and landing system comprises two sources ofelectromagnetic radiation positioned on one side of the center line ofthe take-off and landing platform, the beam of one of these sources isoriented in its own glide slope plane and indicates that glide slope.The second source may be positioned on the same side of the center lineof the take-off and landing platform or on its opposite side, and thebeam of this source of electromagnetic radiation is oriented in its ownglide slope plane and indicates that plane. In combination, these beamsof both sources limit the take-off or landing corridor from the sides.

Finally, these glide slope planes may coincide.

An embodiment of the proposed take-off and landing system wherein thesources of electromagnetic radiation are positioned on either side ofthe center line SS and their beams oriented in a common glide slopeplane is illustrated in FIG. 10.

A first source 1 is placed on one side of the center line SS of atake-off and landing platform 3, whereas a second source 8 is placed onthe other side of the center line SS of this platform 3, and their beams4 and 9 are oriented in a glide slope plane G and indicate that plane G.The sources 1 and 8 of electromagnetic radiation constitute the mainpair of sources. The beams 4 and 9 of the sources 1 and 8 limit atake-off or landing corridor K from both sides. An estimated take-off orlanding path W is the intersection line of a course plane C and theglide slope plane G and lies within said corridor K.

The sources 1 and 8 of electromagnetic radiation may be positioned oneither sadi of the center line SS of the take-off and landing platform 3at any point of a flight platform 2.

FIG. 10 shows the position of these sources 1 and 8 on the flightplatform 2 outside the take-off and landing platform by a dotted line,and a specific embodiment, wherein the sources 1 and 8 are placeddirectly on the take-off and landing platform 3, by a solid line.

There may be other alternatives of placing the sources 1 and 8 ofelectromagnetic radiation, e.g. when these sources are positionedsymmetrically with respect to the center line SS or on side boundaries10 and 10' (FIG. II) of the take-off and landing platform 3, their beams4 and 9 indicating these boundaries.

It should be kept in mind, however, that one of the sources ofelectromagnetic radiation, e.g. the source I, may be positioned directlyon the take-off and landing platform 3 and another, outside thisplatform on the fligh platform 2.

The beams 4 and 9 of the sources I and 8 of electromagnetic radiationpositioned on one side of the center line SS of the take-off and landingplatform 3 may both be directed parallel to the course plane C and forma small angle to this plane. This angle may amount to several angularminutes and reach 1-5°. Such an orientation of the beams 4 and 9 atsmall angles to the course plane C permits the width of the take-off orlanding corridor to become variable, in particular, wider as thedistance from the surface of the take-off and landing platform 3increases.

The table of distortions of the specified cofiguration of the symbol(FIG. 12) produced by projections 5 and II of the beams 4 and 9 forvarious positions of the aircraft A (FIGS. 10 and II) with respect tothe estimated take-off or landing path W is drawn up similarly to thepreviously discussed table (FIGS. 3, 7 and 9). For simplicity's sake,FIG. 12 illustrates the distortions of the specified symbolconfiguration for the case of symmetrical positioning of the sources Iand 8 with respect to the center line SS of the take-off and landingplatform.

The specified symbol configuration for the aircraft's position on thepath W is given as before in the cI square and is made up of theprojections 5 and II of the beams 4 and 9 orthogonal to the vertical 6and extending from arbitrary points 7 and 12 in opposite directions,that is the symbol has a specified configuration of two horizontal linesdisposed on a straight line.

If the aircraft A takes off or lands through the use of theforementioned embodiments of the take-off and landing system of FIGS. 10and II and deviates from the glide slope, still staying in the courseplane C, the specified symbol configuration is distorted so that, whenthe aircraft is above the glide slope of the path W (cII square of FIG.12), the projections 5 and II are directed downward and to the right anddownward and to the left, respectively, of the arbitrary points 7 and12. When the aircraft A is below the glide slope of the path W theprojections 5 and II are directed upward and to the right and upward andto the left, respectively, of the arbitrary points 7 and 12 (cIII squareof FIG. 12). In this case, the projections 5 and II of the beams 4 and 9are disposed symmetrically with respect to the vertical 6.

If the aircraft deviates from the course of the estimated take-off orlanding path W, still staying in the glide slope plane G, the specifiedsymbol configuration (cI square) is not distorted, and only when theaircraft A comes out of the take-off or landing corridor to the left (mIsquare) or to the right (tI square), one of the projections II or 5 ofthe beams 9 or 4 changes its direction for an opposite one, remaininghorizontal.

The table of FIG. 12 uses an additional notation, as compared to that ofFIGS. 3, 7 and 9:

m--the aircraft is to the left of the take-off or landing corridor.

In case the sources I and 8 (FIG. II) of electromagnetic radiation areinstalled on the side boundaties 10 and 10' of the take-off and landingplatform 3, such a reversal of the direction of the projections II and 5of the beams 9 and 4 indicates that the aircraft A is to the left or tothe right of the side boundary 10' or 10 and is outside the limits ofthe take-off and landing platform 3.

If the aircraft A deviates from the course, being, for example, abovethe glide slope of the estimated take-off or landing path W (IIsquares), the specified symbol configuration is distorted as in thetable of FIG. 12. The specified symbol configuration is similarlydistorted when the aircraft A deviates from the course, being below theglide slope of the estimated take-off and landing path W (III squares).In both instances, the symmetry of the projections 5 and II of the beams4 and 9 with respect to the vertical 6 is upset.

It is worth while to dwell once more on the above described tables(FIGS. 2, 3, 7, 9 and 12) and point out some common features of symboldistortions to further simplify the description of the tables ofdistortion of the specified symbol configuration for various deviationsof the aircraft A from the estimated take-off or landing path W.

As is apparent from the tables (FIGS. 2, 3, 7, 9 and 12), in case thebeam 4 (FIGS. 2, 5, 6 and 8) is oriented in the course plane C, thechange of the aircraft A position with respect to the glide slope of theestimated take-off or landing path W, if it is still in the course planeC, involves no change in position of the projection 5 of the beam 4,except when the aircraft A comes out of the boundaries of the corridorK. In this case, the projection 5 of the beam 4 changes its position foran opposite one.

The change of the aircraft's position in the course plane, consequently,involves no angular turn of the projection 5 of the beam 4 situated inthe same course plane. The projection 5 is, in this case, at all timescoincident with the vertical 6.

The process is much the same in case the aircraft A changes its positionin relation to the course of the estimated take-off or landing path Wwithout leaving the glide slope plane G. In this case, the projectionsII (FIG. 7) as well as 5 and II (FIG. 12) of the beams 9 (FIGS. 5 and 6)as well as 4 and 9 (FIGS. 10 and II) do not alter their horizontalposition orthogonal to the vertical 6 and only when the aircraft Aleaves the take-off or landing corridor K, they change their directionfor an opposite one (tI square of FIG. 7 and mI, tI squares of FIG. 12).

When the aircraft A deviates from the course and glide slope of theestimated take-off or landing path W at the same time, the position ofthe projections 5 or II of the beams 4 and 9 changes, including twoturns about the arbitrary points 7 and 12, a turn due to the aircraft'schanging its position in relation to the course and a turn due to achange in position in relation to the glide slope of the estimatedtake-off or landing path W.

Let us consider several embodiments of the proposed take-off and landingsystem when it comprises several pairs of sources of electromagneticradiation.

Thus, if the take-off and landing system comprises two pairs (FIG. 13)of sources of electromagnetic radiation, sources I and 8 constitutingthe main pair of sources are positioned on either side of a center lineSS of a take-off and landing platform 3, their beams 4 and 9 beingdirected in a glide slope plane G₁ of their own. Two other sources 13and 1 are also positioned on either side of the center line SS of thetake-off and landing platform 3, their beams 15 and 16 being directed ina glide slope plane G₂ of their own. Beams 4, 9, 16 and 15 of thesources 1, 8, 14 and 13 limit a take-off or landing corridor K from allsides.

The sources I and 8, 13 and 14 of electromagnetic radiation, placed oneither side of the center line SS of the take-off and landing platform 3may be sited in any place of a flight platform 2.

FIG. 13 shows the location of these sources on the flight platform 2outside the take-off and landing platform 3 by a dotted line and aspecific embodiment, wherein these sources I, 8, 13 and 14 arepositioned on the take-off and landing platform 3, by a solid line.There are other alternatives of positioning these sources, e.g. whensome of them are sited on the take-off and landing platform 3 and some,outside it on the flight platform 2, or when the sources I and 8, 13 and14 of electromagnetic radiation are installed in pairs symmetricallywith respect to the center line SS of the take-off and landing platform3. In one more embodiment (FIG. 14), the sources 1, 8, 13 and 14 ofelectromagnetic radiation are positioned on side boundaris 10' and 10 ofthe take-off and landing platform 3.

In this case the beams 4, 9, 15 and 16 of these sources 1, 8, 13 and 14delineate the side boundaries 10 and 10' of this platform 3. Besides, insome embodiments, the glide slope planes G₁ and G₂ may be parallel.These alternative embodiments are not shown since they do not have anymarked influence on the specified configuration of the symbol producedby electromagnetic beams and on distortions of this specified symbolconfiguration caused by deviations of the aircraft A from the estimatedtake-off or landing path W.

For simplicity's sake, let us assume the estimated take-off or landingpath W of the embodiment of the take-off and landing system of FIGS. 13and 14 to be situated between the glide slope planes G₁ and G₂,equidistant from each of them and lying in the course plane. Inprinciple, though, this path W may be preset arbitrarily and even lie inone of the planes G₁ or G₂.

The specified symbol configuration, when the aircraft A is on theextimated take-off or landing path, is given, as before, in the cIsquare and made up of four projections 5, II, 17 and 18 of the beams 4,9, 15 and 16 of electromagnetic radiation being symmetrical, in pairs,both about the vertical 6 and about the horizontal, that is the lineorthogonal to the vertical 6 (here and henceforth the horizontal is notshown). These projections 5, II, 17 and 18 of the beams 4, 9, 15 and 16diverge in a fan-like fashion from the point A designating the locationof the aircraft A originating from arbitrary points 7, 12, 19 and 20.

When the aircraft A deviates (FIGS. 13 and 14) from the course and glideslope of the estimated take-off or landing path W, the distortion of thespecified configuration of the symbol produced by the projections 5, II,17 and 18 of the electromagnetic beams 4, 9, 15 and 16 may be determinedaccording to the aforementioned rules. A graphic illustration of this isfurnished by the table of distortions of the symbol configuration ofFIG. 15. The distortions of the symbol configuration are an indicationof the direction and magnitude of corrections of a current flight pathof the aircraft A.

Another embodiment of the proposed take-off and landing system withseveral pairs of sources of electromagnetic radiation is one (FIG. 16)comprising three pairs of sources of electromagnetic radiation.

Sources I and 8 constitute the main pair of sources of electromagneticradiation and are positioned on either side of a center line SS of atake-off and landing platform 3, and their beams 4 and 9 are oriented intheir own glide slope plane G₁.

Two other sources 13 and 14 constitute a second pair of sources ofelectromagnetic radiation and are also positioned on either side of thecenter line SS of the take-off and landing platform 3, and their beams15 and 16 are oriented in their own glide slope plane G₂.

Finally, two more sources 21 and 22 constitute a third pair of sourcesof electromagnetic radiation and are positioned similarly to theprevious ones on either side of the center line SS of the take-off andlanding platform 3, and their beams 23 and 24 are oriented in their ownglide slope plane G₃. The glide slope planes G₂ and G₃ are situated oneither side of the glide slope plane G₁ of the main pair of sources.

The beams 15 and 16 of the sources 13 and 14 limit a take-off or landingcorridor K from above, whereas the beams 23 and 24 of the sources 21 and22 of electromagnetic radiation limit this corridor K from below. Thetake-off or landing corridor K is limited, on one side, by the beams 4,15 and 23 of the sources 1, 13 and 21 and by the beams 9, 16 and 24 ofthe sources 8, 14 and 22 on the other side. The sources 1, 13 and 21installed on one side of the conter line SS and the sources 8, 14 and 22installed on the other side of this center line SS of the take-off andlanding platform 3 may be positioned in any place of a flight platform2.

FIG. 16 shows the position of these sources on the flight platform 2outside the limits of the take-off and landing platform 3 by a dottedline and a specific embodiment, wherein these sources 1, 13, 21 and 8,14, 22 are placed on the take-off and landing platform 3, by a solidline. The arrows, like before, indicate possible shifts of thesesources.

There are other alternative embodiments wherein these sources are siteddifferently, e.g. when some of them are installed on the take-off andlanding platform 3 and some outside, on the flight platform 2, or whenthese sources are positioned in pairs symmetrically about the centerline SS of the take-off and landing platform 3. In one more embodiment(FIG. 17), the sources I, 13, 21 and 8, 14, 22 of electromagneticradiation are positioned respectively on side boundaries 10 and 10' ofthe take-off and landing platform 3. In this case, their beams 4, 15, 23and 9, 16, 24 delineate additionally the side boundaries 10 and 10' ofthis platform. Besides, in another embodiment, the glide slope planesG₁, G₂, and G₃ may run parallel.

As far as the beams 4, 15 and 23 of the sources 1, 13 and 21 ofelectromagnetic radiation and the beams 9, 16 and 24 of the sources 8,14 and 22 are concerned, they may be oriented in the glide slope planesG₁, G₂ and G₃ either parallel to the course plane C or form a smallangle to this plane, permitting the take-off or landing corridor K towiden when receding from the surface of the take-off and landingplatform 3. The angles between these beams and the course plane C may beequal to several angular minutes and even several angular degrees.

All this variety of embodiments are not shown, since they do not haveany marked influence on the specified configuration of the symbolproduced by the beams of the sources of electromagnetic radiation, aswell as on the distortions of the specified symbol configuration causedby deviations of the aircraft A from the estimated take-off and landingpath W.

The estimated take-off or landing path W for the embodiment of theproposed take-off and landing system, shown in FIGS. 16 and 17, is theline of intersection of the glide slope plane G₁ and the course plane C.

The specified symbol configuration (FIG. 18), when the aircraft A is onthe estimated take-off or landing path W (FIGS. 16 and 17), is given, asbefore, in the cI square and made up of six projections 5, II, 17, 18,25 and 26 of the electromagnetic beams 4, 9, 15, 16, 23 and 24symmetrical in pairs both to the vertical 6 and to the horizontal, thatis the line orthogonal to the vertical 6. These projections diverge in afan-like fashion from the point A corresponding to the location of theaircraft A originating from arbitrary points 7, 12, 19, 20, 27 and 28.Since the aircraft A is on the estimated take-off or landing path W andin the glide slope plane G₁, the projections 5 and II of the beams 9 and4 look like horizontal lines extending along a straight line. Theprojections 17 and 18 of the beams 15 and 16 are directed upward and indifferent directions. Thus, the projections 17 of the beam 15 isdirected upward and to the right, whereas the projection 18 of the beam16 is pointed upward and to the left. The difference between angles φ₃and φ₄ is 360°, that is the angles are equal if reckoned in differentdirections, one in the negative and the other in the positive direction.

The projections 25 and 26 of the beams 23 and 24 are in perfect analogywith the forementioned ones with the only difference that they aredirected downward and in opposite directions.

If an aircraft takes off or lands through the use of the forementionedembodiment of the proposed take-off and landing system (FIGS. 16 and 17)and deviates from the glide slope of the estimated take-off or landingpath W, still staying in the course plane C, the specified symbolconfiguration (cI square of FIG. 18) is distorted so that the symmetryabout the horizontal is upset, whereas it is preserved in relation tothe vertical 6, that is in relation to the direction of deviations ofthe aircraft A from the estimated take-off or landing path W (csquares).

If the aircraft A takes off or lands and deviates from the course of theestimated path W, still staying in the glide slope plane G₁, thespecified symbol configuration (cI square of FIG. 18) is distorted sothat the symmetry about the vertical 6 is upset and the symmetry aboutthe horizontal is preserved (I squares).

If the aircraft A deviates simultaneously from the course and glideslope of the estimated take-off or landing path W, the specifiedconfiguration of the symbol is distorted with the symmetry about thevertical 6 and the horizontal being upset at the same time. This can beseen from the table of distortions of the symbol configuration of FIG.18.

Changes in the direction of some projections may help to determine ifthe aircraft A is outside the limits of the take-off or landing corridorK. One more simple rule may be used here and it is illustrated in FIG.18. If all the projections 5, II, 17, 18, 25 and 26 of the beams 4, 9,15, 16, 23 and 24 extend predominantly in the same direction, e.g. tothe left and downward (tV square) of the arbitrary points 7, 12, 19, 20,27 and 28, that means that the aircraft A is on a side opposite to thetake-off or landing corridor, to the right and upward of this corridor Kin the above cited example, etc.

If, in this case, the sources 1, 8, 13, 14, 21 and 22 are installed onthe side boundaries 10 and 10' of the take-off and landing platform 3,as shown in FIG. 17, deviations of the aircraft A from the take-off orlanding corridor K to the right or to the left indicates that theaircraft is respectively to the left or right of the take-off andlanding platform 3.

The proposed take-off and landing system may have other embodiments.Thus, for example, it may comprise, apart from one or several pairs ofsources of electromagnetic radiation, one more source to be installed asin the embodiment of FIG. 2, that is on the conter line of the take-offand landing platform.

An example of this embodiment is a system (FIG. 19) comprising twosources I and 8 of electromagnetic radiation, constituting the mainpair, positioned on either side of a center line SS of a take-off andlanding platform 3, their beams 4 and 9 being oriented in a glide slopeplane G, and a third source 29 positioned on the center line SS of thetake-off and landing platform 3, its beam 30 being oriented in a courseplane C. The source 29 may be installed in any place of the center lineSS of the take-off and landing platform 3, or ahead of this platform onthe extension of its center line SS, its beam 30 being below or abovethe glide slope plane G, or crossing this glide slope plane G. The solidline indicates the location of the source 29 with its beam directedabove the glide slope plane G, and the dotted line indicates analternative location of this source 29 when its beam is below the glideslope plane G. The arrows show possible shifts of all the three sourcesI, 8 and 29 of electromagnetic radiation.

There is another embodiment of the take-off and landing system (FIG. 20)comprising, for example, five sources of electromagnetic radiation. Forsimplicity, a case is considered when two sources I and 8 ofelectromagnetic radiation constitute the main pair of sources and areinstalled on either side of a center line SS of a tale-off and landingplatform 3 on its side boundaries 10 and 10' with beams 4 and 9 beingoriented in their own glide slope plane G₁. Two other sources 13 and 14constitute a second pair and are also installed on either side of thecenter line SS of the take-off and landing platform 3 on its sideboundaries with beams 15 and 16 being oriented in their own glide slopeplane G₂. Finally, a fifth source 29 is installed on the center line SSof the take-off and landing platform 3, its beam being oriented in acourse plane C. The source 29 may be installed in any place on thecenter line SS, as well as ahead of this platform 3 on the extension ofthe center line SS, and its beam 30 may be positioned above the glideslope planes G₁ and G₂ (indicated by a solid line in FIG. 20), below theplanes G₁ and G₂ (indicated by a dotted line in FIG. 20), in one of theplanes G₁ or G₂, or cross these planes G₁ and/or G₂. The arrow indicatesthe direction of possible shifts of the source 29 of electromagneticradiation.

There are other embodiments of the proposed take-off and landing system,e.g. when it comprises seven sources of electromagnetic radiation, thatis three pairs of these sources positioned as in FIG. 16 and a seventhsource placed on the center line SS of the take-off and landing platform3, etc. These embodiments are not shown.

The specified symbol configuration produced by the beams of the sourcesof electromagnetic radiation, as well as distortions of thisconfiguration for various deviations of the aircraft A from theestimated take-off or landing path W in accordance with the abovedescribed embodiments of the take-off and landing system (FIGS. 19 and20) are not shown because of their simplicity.

FIG. 21 shows an embodiment of the take-off and landing system of FIG.19, wherein the sources I and 8 of electromagnetic radiation areinstalled on the side boundaries 10 and 10' of the take-off and landingplatform 3 and the source 29 is installed on the center line SS of thisplatform 3 so that its beam 30 is below the glide slope plane G producedby the beams 4 and 9 of the sources I and 8.

The beams 4, 9, 30 of the sources I, 8 and 29 of electromagneticradiation may be directed in parallel or form the take-off or landingcorridor K widening with distance from the take-off and landing platform3.

In this case, the beams 4 and 9 of the sources I and 8 may form a smallangle to the course plane C of the order of several angular minutes oreven 1°-5°, and the beam 30 of the source 29 may be directed at the sameangle to the glide slope plane G.

The take-off or landing corridor K is formed by the beams 4, 9 and 30 ofthe sources 1, 8 and 29, the beams 4 and 9 being the side limits of thecorridor K and, simultaneously indications of the boundaries 10 and 10'of the take-off and landing platform 3, whereas the third beam 30 limitsthis corridor from below.

The specified symbol configuration (cI square of FIG. 22) when theaircraft A is on the extimated take-off or landing path W (FIG. 21), ismade up of three projections 5, II and 31 of the electromagnetic beams4, 9 and 30 looking like two horizontal lines and one vertical line. Theprojections 5 and II of the beams 4 and 9 are positioned horizontallyalong one straight line, whereas the projection 31 of the beam 30 ispositioned vertically and coincides with the vertical 6, so that thespecified symbol configuration has a T shape. The specified symbol issymmetrical about the vertical 6.

If an aircraft takes off or lands through the use of the above describedembodiment of the take-off and landing system (FIG. 21) and deviatesfrom the glide slope of the estimated take-off or landing path W, stillstaying in the course plane C, the specified symbol configuration isdistorted, and the projections 5 and II of the beams 4 and 9 aredeflected from the horizontal direction, turning to each other inrelation to arbitrary points 7 and 12 (c squares of FIG. 22). Thevertical position of the projection 31 of the beam 30 is retained, andonly when the aircraft A is below the take-off or landing corridor K(cIV square), the projection 31 of the beam 30 changes its direction foran opposite one.

If an aircraft takes off or lands and deviates from the course of theestimated path W, still staying in the glide slope plane G, thespecified symbol configuration is distorted so that the projection 31 ofthe beam 30 deflects from the vertical 6, turning about the arbitrarypoint 32 (I squares). The horizontal position of the projections 5 andII of the beams 4 and 9 is retained, and only when the aircraft A is tothe left (mI square) or to the right (tI square) of the take-off orlanding corridor K, one of these projections II or 5 respectivelychanges its position for an opposite one.

Distortions of the specified symbol configuration in case of otherdeviations of the aircraft A from the estimated path W are shown in FIG.22. The fact that the aircraft A is outside the limits of the take-offor landing corridor K may be determined with the help of the simple rulementioned above. According to this rule, the aircraft A is in theopposite direction from the take-off or landing corridor K in relationto some common direction wherein all the projections 5, II and 31 of thebeams 4, 9 and 30 extend. When, for example, all projections in the tIVsquare are directed upward and to the left, this means that the aircraftA is downward and to the right of the estimated path W.

The symbol (FIG. 22) formed by the three beams 4, 9 and 30 has aconfiguration asymmetric with respect to the horizontal which makesdetermination of the "up/down" direction easier because each embodimentprovides for a particular arrangement of the beam 30 with respect to theglide slope plane D. In the embodiment of FIG. 21, this beam is alwaysbelow the glide slope plane G and the projection 31 of the beam 30 isalways below the projections 5 and II.

There is another embodiment of the take-off and landing system (FIG.23), comprising four sources of electromagnetic radiation, two of them Iand 8 forming the main pair of sources and are installed on either sideof a center line SS of a take-off and landing platform 3, whereas twoothers 29 and 33 are installed on the center line SS on either side of aglide slope plane G. Beams 4 and 9 of the sources I and 8 ofelectromagnetic radiation are oriented in the glide slope plane G andindicate that plane, whereas beams 30 and 34 of the sources 29 and 33are oriented in a course plane C and indicate the course of theestimated take-off or landing path W.

The beams 4 and 9 limit a take-off or landing corridor K from the sidesand the beams 30 and 34 limit it from below and from above,respectively. As has been mentioned before, the sources I and 8 may bepositioned both on a flight platform 2 and on the take-off and landingplatform 3. FIG. 23 illustrates the position of these sources I and 8 onside boundaries 10 and 10' of the take-off and landing platform 3.

The specified symbol configuration produced by projections of the beams1, 8, 30 and 34 of electromagnetic radiation looks like two horizontaland two vertical lines running into one another and may be easilyobtained by superimposing the specified symbol configuration of FIG. 9over that of FIG. 12 (cI squares). On the whole, the symbol looks likethe sign "+". Distortions of the specified symbol configuration may beeasily obtained by superimposing respective squares of FIGS. 9 and 12.Because of its simpliciry, the table of distortions of the specifiedsymbol configuration for this embodiment of the take-off and landingsystem (FIG. 23) is not shown.

The above described embodiments of the proposed take-off and landingsystem comprise sources of electromagnetic radiation functionallyconstituting a course and glide slope group. The beams of these sourcesof electromagnetic radiation produce a symbol of a specifiedconfiguration and form a take-off or landing corridor wherein a take-offor landing path lies. The distortions of the specified symbolconfiguration indicate that an aircraft deviates from the course andglide slope of the estimated take-off or landing path, as well as isoutside the limits of the take-off or landing corridor. Being outsidethe corridor is determined by predominant orientation of electromagneticbeam projections in some common direction, which measn that the aircraftis in the opposite direction from the take-off or landing corridor(FIGS. 15, 18, 22).

Besides, this symbol formed by electromagnetic beams permits detectionof the aircraft's bank and determination of its magnitude. The bank ofan aircraft may be determined by that the symbol turns as an entity,without distortion of its configuration, about an axis passing throughthe point A which is the location of the aircraft (FIGS. 12, 15, 18 and22). The symbol turns in the direction opposite to the aircraft bank.

Moreover, in fact the symbol remains stationary: it is the aircraft thatbanks, but it is percepted on board the aircraft as a turn of thesymbol.

The bank is much more easily and vividly perceived when the specifiedsymbol configuration has horizontal projections indicating the line ofhorizon (FIGS. 12, 18, 22).

It should be pointed out that no localizer and glide slope transmittersystem employed currently in the world, including the Instrument LandingSystem, incorporates this feature and, because of its design features,provides no information as to aircraft's bank. To determine the bank ofan aircraft, the pilot has to consult instruments, the gyro horizon inparticular.

The take-off or landing corridor produced by the beams of the sources ofelectromagnetic radiation of the course and glide slope group performone more vital function substantially facilitating the process of flyingan aircraft. This resides in the fact that the take-off or landingcorridor as though prolongs the take-off and landing platform,permitting the pilot to control the attitude of the aircraft withrespect to the take-off or landing corridor so that it satisfies theconditions of maximum safety. This is very easily done if the system ismade up of collimated pencil beams of electromagnetic radiation withinthe optical band. In this case, the pilot is able to see the boundariesof the take-off or landing corridor due to stereoscopic vision effects.The beams visible in space play the part of approach and lead-in lightsusually positioned on the ground as an extension of a runway, but playit more effectively since they are situated in space. This peculiarityof the take-off or landing corridor is of particular value for aircraftlanding on a carrier deck, which is to be dealt in detail later, sincein this case no analogy to ground approach and lead-in lights can bedrawn.

The forementioned embodiments of the proposed take-off and landingsystem cannot by far exhaust the variety of possible alternatives. Thedescribed sources of electromagnetic radiation positioned on a take-offand landing platform may be supplemented by any number of sourcesrequired for creating more complex symbols and more strict limiting of atake-off or landing corridor.

The proposed take-off and landing system has other embodiments whereinthe side boundaries and the center line of the take-off and landingplatform are indicated by the beams of the sources of electromagneticradiation installed on the side boundaries and the center line of thisplatform specifically for this purpose. These sources form the landinglights group and serve to orient an aircraft with respect to the sideboundaries and the center line of the take-off and landing platform atthe last stage of landing, immediately before touchdown, during thelanding run, as well as during the take-off run, and in the course ofclimbing.

The description of take-off and landing systems equipped with additionalsources of electromagnetic radiation constituting the landing group willomit the sources constituting the course and glide slope group to avoidencumbering the figures.

If the proposed take-off and landing system (FIG. 24) comprises one pairof additional sources of electromagnetic radiation, these sources 35 areinstalled on a flight platform 2 in the immediate vicinity of the end ofa take-off and landing platform 3 on either side of its center line SSon the extension of side boundaries 10 and 10' of this platform 3. Beams36 of the sources 35 of electromagnetic radiation are directed parallelto the surface of the take-off and landing platform 3 along the sideboundaries 10 and 10' of this platform 3.

The beam 36 of the sources 35 should be directed so that they are levelwith the receiver of electromagnetic radiation carried by an aircraft orlevel with the pilot's eyes. If the wavelength of electromagneticradiation employed to produce the beams 36 lies in the invisible band,the symbol formed by these beams 36 is detected only by specialreceivers aboard the aircraft, and the system becomes purelyinstrumental. If, however, the wavelength is selected within the visibleband of the electromagnetic radiation spectrum, the beams 36 can beperceived visually. It should not be ignored, however, that radiation inthe visible band can be detected by instrumental means, that is thesystem may be made as both visual and instrumental.

The specified symbol configuration (FIG. 25), when an aircraft A is onthe surface of the take-off and landing platform 3 is presented, asbefore, in the cI square and is formed by projections 37 of theelectromagnetic beams 36 looking like two horizontal lines at an angleof 90° to the vertical 6.

Unlike in previous descriptions, "I" stands for the position of theaircraft A on the surface of the take-off and landing platform 3 (FIG.24) and "II" designates its position above the surface of the take-offand landing platform 3.

When an aircraft is to the right (rI square) or left (II square) of thecenter line SS of the take-off and landing platform 3, the specifiedsymbol configuration is not distorted.

If an aircraft takes off or lands and is above the surface of thetake-off and landing platform 3, still staying in the course plane C,the specified symbol configuration is distorted but remains symmetricalabout the vertical 6 (cII square).

If the aircraft A is at the same time to the left or right of the courseplane C, the symmetry of the symbol configuration is also upset. Thefact that the aircraft A is outside the boundaries 10 or 10' of thetake-off and landing platform 3 may be determined by a commonorientation of the projections 37 originating at arbitrary points 38(tII and mII squares). Such orientation of the projections 37 ischaracteristic of deviations of the aircraft A in a direction oppositeto the common direction of these projections 37.

In principle, another arrangement of the sources 35 of electromagneticradiation is possible, e.g. at the beginning of a take-off and landingplatform. In this case, an aircraft moves along the beam 36 and nottoward the beam 36, as in FIG. 24.

Another embodiment (FIG. 26) of the take-off and landing platform 3designation comprises an additional source 39 on a flight platform 2 inthe immediate vicinity of the end of the take-off and landing platform 3on its conter line SS. A beam 40 of the source 39 is directed parallelto the surface of the take-off and landing platform 3, lies in a courseplane C and indicates the conter line SS of this platform 3.

The distortions of the specified configuration of the symbol produced bya projection 41 of the electromagnetic beam 40 originating at anarbitrary point 42 are illustrated in FIG. 27. It is simple and graphicand needs no detailed description. It should be noted, however, that, ifthe beam 40 of the source 39 is below the level of an airborne receiverof electromagnetic radiation or of the pilot's eyes, the symbol producedby the beam 40 when the aircraft A is on the surface of the take-off andlanding platform 3 on its center line SS and looks like in the cIIsquare.

One more embodiment of the take-off and landing system (FIG. 28)comprises three sources of electromagnetic radiation, constituting thelanding lights group, two (35) of these sources being installed on aflight platform 2 in the immediate vicinity of the end of a take-off andlanding platform 3 on either side of its center line SS on its sideboundaries 10 and 10', whereas the third source (39) is positioned onthe flight platform 2 in the immediate vicinity of the end of thetake-off and landing platform 3 on its center line SS. Beams 36 and 40of these sources 35 and 39 are directed parallel to the surface of thetake-off and landing platform 3. The beams 36 of the sources 35 aredirected along the side boundaries 10 and 10' of the take-off andlanding platform 3, whereas the beam 40 of the source 39 is directedalong the center line SS of this platform 3.

The symbol produced by the beams 36 and 40 is presented in FIG. 29. Itis simple and easy to memorize and is a combination of the two symbolsof FIGS. 25 and 27.

In some cases, the purposes of additional designation of the take-offand landing platform boundaries may require installation of any numberof sources of electromagnetic radiation along its sides. This may be dueto uneven surface of a take-off and landing platform or a plurality oftaxiways on a ground airfield. In such cases, the beams of sources ofelectromagnetic radiation serve as additional indications of theboundaries of the take-off and landing platform. If, for example, thesurface of a take-off and landing platform rises smoothly at first, thenlowers somewhere from the middle, and the end of the platform cannot beseen from its beginning, an additional pair of sources ofelectromagnetic radiation is installed on its side boundaries at thehighest point, their beams serving as additional indicators of the sideboundaries of the take-off and landing platform.

It should be emphasized that the described group of sources ofelectromagnetic radiation, constituting the landing lights group, may beinstalled in combination with any of the forementioned take-off andlanding systems illustrated, for example, in FIGS. 1, 2, 4, 5, 6, 8, 10,11, 13, 14, 16, 17, 19, 20, 21, 23.

The beams of the sources of electromagnetic radiation, constituting thelanding lights group, produce a symbol similar to the one produced bythe beams of the sources constituting the course and glide slope group.This makes piloting of an aircraft using a take-off and landing systemmuch easier, when the proposed take-off and landing system is made asvisual, and simplifies designing airborne receivers, when this system ismade as instrumental, permitting development of uncomplicated andreliable automatic equipment for operation at all stages of the aircrafttake-off and landing. Besides, the above-described take-off and landingsystem remains the same both for take-off and landing of an aircraft.

The proposed take-off and landing system, as has already been mentionedbefore, may comprise one more group of sources of electromagneticradiation, constituting a group of marker sources, intersections oftheir beams being indications of various marker points, e.g. the flareinitiation point or the point designating an assigned distance to thetake-off and landing platform. Such an addigned distance may be thedistance to one of the homing stations, e.g. the inner, middle or outermarker locators.

Similarly to the description of take-off and landing systems comprisingthe landing lights group, the figures show only the sources with beamsindicating marker points to avoid encumbering the drawings.

A pair of additional sources 43 (FIG. 30) is installed on a flightplatform 2 and their beams 44 are directed so as to intersect at anassigned distance in spece and form a marker point 45.

This point 45 may be situated both in a course plane C and near thisplane, as well as on an estimated take-off or landing path W.

An embodiment featuring a symmetrical location of these sources 43 isillustrated in FIG. 31. The marker point 45 in this case designates theassigned distance to a homing station 46 and is positioned a bit lowerthan the estimated take-off or landing path W in the course plane C.

The specified exmbol produced by projections of the beams 44 of thesources 43 of electromagnetic radiation may have two differentconfigurations. If the sources 43 are situtated below the glide slopeplane G (FIG. 31) and their beams 44 do not intersect this plane G, thespecified symbol configuration presented in FIG. 32 in the squaredesignated as VII is formed by two projections 47 of the beams 44originating at arbitrary points 48 and directed vertically downward.

The following notations are used in FIG. 32.

VI--the aircraft is beyond the distance to the marker point 45indicating the assigned distance, e.g. the flare initiation point of theaircraft A or the point designating one of the homing stations;

VII--the aircraft is at the assigned distance from the take-off andlanding platform, corresponding to the flare initiation or to the momentthe aircraft is overhead one of the homing stations;

VIII--the aircraft is closer to the runway than the marker point.

If the aircraft A is beyond the distance to the marker point 45, thedistortion of the symbol configuration looks like that in the VI squareof FIG. 32. The projections 47 of the beams 44 intersect.

If the aircraft A is closer to the take-off and landing platform thanthe marker point 45, the projections 47 diverge without intersecting(the VIII square of FIG. 32).

In case the beams 14 of the sources 43 intersect the glide slope G, thespecified symbol configuration (FIG. 33) is different (VII square). Inthis case, the symbol is formed by the two projections 47 of the beams44 originating at the arbitrary points 48 and directed horizontallytoward each other. If the proposed take-off and landing system is madeas a visual one, the pilot can notice the moment of passing the markerpoint by a short flash.

The distortion of the specified symbol configuration, when the aircraftA is farther or closer to the take-off and landing platform than themarker point 45, is given in VI and VIII squares.

If the system uses electromagnetic radiation in the visual band, thepilot is able to see the intersection point in space and judge by thedistortion of the symbol about the distance to this point, whichconsiderably simplifies piloting the aircraft.

The symbol produced by the beams of the marker group sources is similarto that produced by the beams of the sources of electromagneticradiation of the forementioned qroups. And when the system is madeinstrumental, the same aircraft equipment may be employed to detect thesymbol. It simplifies the process of automatic landing and is animportant advantage of the proposed system over the existing ones.

The group of marker sources of electromagnetic radiation permitsdesignation of various marker points, which cannot be designated by anyother means, e.g. in inaccessible mountainous regions and over the seasurface in the case of landing on a carrier deck.

Marker points are as a rule employed for aircraft landing, but may bealso used for distance monitoring during take-off.

A group of marker sources may be installed in combination with any oneof the forementioned take-off and landing systems, comprising the courseand glide slope group and the landing lights group.

FIG. 34 illustrates by way of example an embodiment of the take-off andlanding system, comprising all three groups of sources ofelectromagnetic radiation, in particular, the course and glide slopegroup of FIG. 21, the landing lights group of FIG. 24 and the merkergroup of FIG. 31. FIG. 34 shows two marker points 45.

One of them, which is nearer to the take-off and landing platform is theflare initiation point, and the other point 45 designates the assigneddistance to the homing station 46. All these groups of sources and thesymbol produced by the beams of each of the groups are described indetail earlier. The symbol produced by the beams of the sources ofelectromagnetic radiation positioned as in FIG. 34 is the totality ofthe symbols produced by the beams of each group of sourcesindependently.

If the take-off and landing system is made visual, that iselectromagnetic radiation in the visual band is used, the beams of thesources making up different groups may be of different color.

Thus, for example, the beams 4 and 9 (FIG. 34) may be red andhelium-neon lasers are used as the sources I and 8 of electromagneticradiation, the beam 30 is green, its source being an argon laser.Finally, the beams 36 may be dark red, their sources 35 being kryptonlasers, and the beams 44 designating the marker points 45 are orange oryellow, their sources 43 being lasers generating in the orange or yellowregion. For simplicity, however, all beams with be assumed to be of onecolor, e.g. red or orange, produced by one type of lasers used assources of electromagnetic radiation.

To increase the renge of the system in dense fog, all or some beams maybe produced by a combination of several wavelengths of electromagneticradiation. For example, the beams 4, 9 and 30 (FIG. 34) may be formed bycombining electromagnetic radiation of the visible and infrared ranges.In this case, the infrared radiation forms a channel in the fog andcreates conditions for passing visible radiation, ensuring introductionof more rigid take-off and landing minima.

The use of aircraft receivers operating in the visible band ofelectromagnetic radiation permits displaying the distortion of thespecified symbol configuration on an instrument installed in the pilot'scockpit, as well as making up automatic equipment. In this case, thesystem becomes instrumental and remains visual at the same time.

The visual embodiment of the proposed take-off and landing system.However, when no equipment is installed aboard the aircraft, is still areliable instrumental means ensuring manual take-off and landing. Theinstrument ensuring high accuracy of determination of the aircraft'sposition in space with respect to the estimated take-off or landing pathW is the symbol produced in space by visible electromagnetic beams. Theproposed take-off and landing system possesses a very high degree ofaccuracy in determination of aircraft's deviations from the estimatedtake-off or landing path surpassing the accuracy of currently employedradio localizer and glide slope transmitter systems in some cases by asmany as a hundred or even thousand times. The degree of distortion ofthe specified symbol configuration permits determination of aircraftdeviations from the assigned take-off or landing path W within the rangeof several centimeters.

That is why even the visual embodiment of the proposed take-off andlanding system may be regarded as an instrumental means of a very highdegree of accuracy. It should be once more emphasized that no equipmentis in this case installed in the aircraft.

There are two embodiments of positioning the sources of electromagneticradiation, constituting the course and glide slope group in accordancewith the proposed take-off and landing system, on a flight platform. Ina take-off version of the system, the sources are placed near theaircraft lift-off point and, in its landing version, these sources arepositioned in the immediate vicinity of the beginning of a take-off andlanding platform. As has been mentioned above, in all the foregoingfigures, the arrow L indicates the direction of landing of the aircraftA and the arrow F indicates the direction of its take-off. None of thesefifures point the exact location of sources on the center line SS of thetake-off and landing platform, but it should be kept in mind that, inthe take-off version, they are to be located in near the lift-off pointand, in the landing version, in the beginning of the take-off andlanding platform.

The take-off version of the proposed take-off and landing system isillustrated in FIG. 35, wherein letter V denotes the lift-off point ofthe aircraft A. Letter W, in this case, designates an estimated take-offpath, K stands for a take-off corridor. The glide slope plane G is inthis case the take-off path plane.

Beams 4, 9, 30 of sources I, 8 and 29 of electromagnetic radiationindicate the course and glide slope of the estimater take-off path W.

The landing version of the proposed take-off and landing system isillustrated in FIG. 34 described above. The beams 4, 9 and 30, in thiscase, indicate the course and glide slope of a landing path W and acorridor K formed by these beams is the landing corridor.

To cut down the landing distance and reduce noise in the airfield areaduring aircraft landings, as well as to ensure landing of VTOL aircraftand helicopters, the estimates landing path may be made as a broken linecomprising separate legs inclined differently in relation to thehorizon. The glide slope planes, indicated by the beams of the sourcesof electromagnetic radiation, of each leg of the landing path arerespectively directed at different angles to the horizon. Such a path,for example, may have one bend.

For simplicity, FIG. 36 shows an example of an embodiment of thetake-off and landing system ensuring aircraft landing along a concaveestimated landing path with one bend. Three sources I, 8 and 29 ofelectromagnetic radiation are installed on a flight platform 2 in theimmediate vicinity of the beginning of the take-off and landing platform3, and three auxiliary sources I', 8' and 29' are situated before thetake-off and landing platform. The auxiliary sources I', 8' and 29' arepositioned, in this example, like the sources 1, 8 and 29.

To avoid encumbering the figure, it shows the sources of electromagneticradiation forming the course and glide slope group only.

Beams 4 and 9 of the sources I and 8 of electromagnetic radiation areoriented in a glide slope plane G, whereas beams 4' and 9' of thesources I' and 8' are oriented in another glide slope plane G₄, thisplane G₄ being tilted at a greater angle in comparison with the plane G.The planes G₄ and G of glide slopes intersect. The estimated landingpath is the line of intersection of the glide slope planes G and G₄ anda course plane C. This path consists of two legs, the leg W₂ beinginclined at a greater angle to the surface of the take-off and landingplatform 3 and the leg W₁ inclined at a smaller angle to the surface ofthe take-off and landing platform 3.

The specified symbol configuration produced by projections of beams 4, 9and 30 and 4', 9' and 30', as well as distortions of this specifiedconfiguration for various deviations of the aircraft from the estimatedlanding path at its both legs W₂ and W₁ are given in FIG. 22.

It should be remembered that the auxiliary sources of electromagneticradiation installed on a flight platform before the take-off and landingplatform may be arranged differently, unlike to sources placed in theimmediate vicinity of the beginning of the take-off and landingplatform. Moreover, the number of these sources may be different. Forexample, the sources of electromagnetic radiation positioned in theimmediate vicinity of the beginning of the take-off and landing platformmay be arranged as in FIGS. 5, 15 or 20, whereas the auxiliary sourcespositioned before the take-off and landing platform may be arranged asin FIGS. 2, 11, 17 or 21. In this case, the pecified symbolconfiguration changes when the aircraft passes from one leg of the pathot another.

The proposed take-off and landing system in any one of its variousembodiments may be installed on flight platforms of various groundairfields, water surface or ship landing decks. Depending on thefunctional requirements set to a take-off and landing system installedon a take-off and landing platform being a ship landing deck, one orseveral sources of electromagnetic radiation are placed so that theirbeams produce a symbol and indicate the course and glide slope of anestimated take-off or landing path and carry additional information asto the deck's motions not only at the points of their installation butas a whole. The principles of symbol production and determination of anaircraft's position with respect to an estimated take-off or landingpath by the distortion of this symbol configuration have been dealt within detail hereinabove.

The figures given below show only those sources which form the courseand glide slope group to avoid encumbering the drawings, andexplanations are supplied pertaining to the additional information onship deck motions carried by the beams of the sources of electromagneticradiation comprising the course and glide slope group. Only at the end,there is a detailed description of an embodiment of the take-off andlanding system installed on the landing deck of a ship.

Here, chief emphasis is laid on the performance of landing on a shiplanding deck, since this process is the most complicated and critical.

If the take-off and landing system is made as in FIG. 2, a source I ofelectromagnetic radiation (FIG. 37) is installed on a center line SS ofa landing deck 3 of a ship 49, in the immediate vicinity of an estimatedtouchdown zone 50 of an aircraft A on the surface of the deck 3. A beam4 of the source I indicates motions of the deck in the touchdown zone 50resulting from rolling and pitching, yawing and up-and-down motions ofthe ship 49 caused by the rough sea. If the source I is installed on agyro-stabilized platform 51, angular motions of the beam 4 caused byangular motions of the hull of the ship 49 and its deck 3 resulting fromrolling, pitching and yawing are eliminated, but not the linear motionsof the beam 4 caused by those motions of the hull of the ship 49 and itsup-and-down motion on waves. Since such motions are the most dangerousin the process of landing of the aircraft A on the deck 3, due tochanges in the position of the estimated landing path W they cause,availability of information free of redundant data is a great assistancein piloting the aircraft A during landing with higher safety.

The information on linear motions of the surface of the landing deck 3of the ship 49 in the immediate vicinity of the estimated touchdown zone50 of the aircraft A are perceived by the distortions of the specifiedconfiguration of the symbol. The estimated landing path W and the beam 4change their position with respect to the aircraft A due to linearmotions of the landing deck 3, which may be regarded as a change inposition of the aircraft A with respect to the estimated landing path Wwhen it is stationary. In this case, the specified symbol configurationillustrated in FIG. 3 for this embodiment of the proposed system, isdistorted through deviations of the aircraft A from the estimated path Wand through the change in position of the path W in space. Thedistortion of the specified symbol configuration is an indication of themagnitude and direction of deviations of the aircraft A from theestimated path, as well as of the direction of correction of its currentflight path. The motions of the deck 3 of the ship 49 are periodicoscillations with a period of several seconds and can be detected byperiodic distortions of the symbol configuration, which facilitates theprocess of landing, particularly at the last stage, immediately beforethe aircraft A touches the deck 3.

The proposed take-off and landing system positioned on a take-off andlanding platform being the landing deck 3 of the ship 49 (FIG. 38) mayhave other embodiments, e.g. the one presented in FIG. 8. In this case,a first source I of electromagnetic radiation is installed on a centerline SS of the landing deck 3 of the ship 49 in the immediate vicinityof an estimated touchdown zone 50 on the surface of the deck 3. A secondsource 8 is placed on a stern edge 52 of the landing deck 3. A beam 4 ofthe source I indicates the motions of the landing deck 3 in thetouchdown zone 50, whereas a beam of the source 8 indicates the motionsof the stern edge 52 of the landing deck 3. The causes of these motionshave been dealt with in detail above. It should be pointed out that themagnitude of motions of the stern edge 52 is significantly greater ascompared to the magnitude of those of the deck 3 in the immediatevicinity of the touchdown zone 50, because the stern edge 52 isconsiderably farther from the center of gravity of the ship 49. It iscommon knowledge that angular motions take place around the center ofgravity of a system, in particular, a ship.

In the course of landing, the aircraft A flies overhead the stern edge52 of the landing deck 3, and, for safety reasons, it is necessary toknow how the stern edge 52 moves. Besides, the beams 4 and 9 of thesources I and 8, while moving together in space, serve as an indicationof the inclination of the landing deck 3 along its center line SS, thatis an indication of longitudinal angular motions of this deck 3.

The sources I and 8 may be installed on gyro-stabilized platform 51eliminating angular motions of the beams 4 and 9 in space.

Information on linear motions of the surface of the landing deck 3 ofthe ship 49 in the immediate vicinity of the touchdown zone 50 on thedeck 3, as well as its stern edge 52, is perceived aboard the aircraft Aby distortions of the specified symbol configuration. Distortions of thespecified symbol configuration of FIG. 9 permit determination of themagnitude and direction of deviations of the aircraft A from theestimated take-off or landing path moving, as has been already mentionedabove, in space.

In this case, a projection II of the beam 9 changes its position withinthe structure of the symbol configuration more than a projection 5 ofthe beam 4. It is this change that characterizes the motions of thestern edge 52. Besides, distortions of the symbol configuration areindicative of the displacement of a landing corridor K in space. Theposition of the aircraft A with respect to the estimated path W andlanding corridor K is determined exactly as has been described earlier.

The proposed take-off and landing system installed on the deck 3 of theship 49 (FIG. 39) may be arranged as in the embodiment of FIG. II. Inthis case the sources I and 8 of electromagnetic radiation constitutethe main pair and are positioned on the opposite side boundaries 10 and10' of the landing deck 3 in the immediate vicinity of the touchdownzone 50 of the aircraft A on the landing deck 3. The beams 4 and 9 ofthese sources I and 8 are oriented, as has been mentioned before, in thecommon glide slope plane G. They indicate the course and glide slope ofthe estimated landing path W and, in addition, motions of the landingdeck 3 in the touchdown zone 50.

Motions of the landing deck 3, caused by instability of the ship 49 onthe rough surface of the sea, cause motions of the sources I and 8installed on the deck 3. As has been mentioned before, if the sources Iand 8 are mounted on the gyro-stabilized platform 51, angular motions ofthese sources I and 8 and the beams 4 and 9 are eliminated, but linearmotions of these sources I and 8 equal to those of the landing deck 3 inthe places of their location continue. Linear motion of the sources Iand 8 result in linear displacements in space of the beams 4 and 9produced by these sources. Considering that the source 8 positioned onthe outer side boundary 10' of the landing deck 3 is farther from theship's center of gravity than the source I, linear motions of thissource 8 caused by rolling of the ship are greater than those of thesource I. Consequently, displacement of the beam 9 in space is greaterthan that of the beam 4. FIG. 39 shows the displacement of the beam 9 bya dotted line and an arbitrary zone 53 wherein the beam 9 movesremaining parallel to itself. Similarly shown is an arbitrary zone 54,wherein the beam 4 of the source I of electromagnetic radiation alsomoves remaining parallel to itself. Parallelism of movements of thebeams 4 and 9 in space is due to gyro-stabilization. Since the beams 4and 9 indicate the glide slope plane, displacement of these beams inspace indicates displacement of the glide slope plane and, inparticular, its angular displacement being indicative of the heel of thelanding deck 3 at the points of location of the sources I and 8. Thetable of distortions of the specified symbol configuration for thisembodiment (FIG. 39) with the sources I and 8 of electromagneticradiation is illustrated in FIG. 12.

As has already been mentioned above, the motions of the landing deck 3(FIG. 39) result, ultimately, in displacement of the estimated landingpath W in space. Changes in position of the aircraft A with respect tothe estimated landing path W causes distortions of the specified symbolconfiguration indicative of the magnitude and direction of deviations ofthe aircraft A with respect to the estimated landing path W. Consideringthat the heeling of the landing deck 3 brings about different linearmotions of the sources I and 8, the symbol produced by the beams 4 and 9of these sources I and 8 turns angularly as a whole. Such turns of thesymbol are indications of the heel of the landing deck 3 in theimmediate vicinity of the touchdown zone of the aircraft A on thelanding deck 3 and its magnitude.

Other embodiments of the proposed take-off and landing system may beinstalled on a take-off and landing platform being the landing deck of aship, e.g. the embodiment of FIG. 14. In this case, the sources ofelectromagnetic radiation constituting the main pair are positioned onthe opposite boundaries of the landing deck in the immediate vicinity ofthe aircraft touch down zone on the landing deck, whereas two othersources constituting the second pair are also positioned on the oppositeboundaries of the landing deck between the stern edge and the main pairof sources. The beams of the sources of electromagnetic radiation of thesecond pair indicate the near limit of the aircraft touchdown zone onthe landing deck. This embodiment is not shown because of itssimplicity, the arrangement of the sources being easily understtod fromFIG. 14.

It should be pointed out that FIG. 14 illustrates an example ofarrangement of the sources of electromagnetic radiation, wherein thesecond pair of sources is positioned behind the main pair. In contrast,their position on a ship landing deck should be reversed. Distortions ofthe symbol configuration caused by deviations of an aircraft from anestimated landing path are similar to those of FIG. 15. Besides, as hasbeen described above, angular turns of the symbol as a whole areindicative of the heel of the landing deck. Considering that the secondpair of sources is farther from the ship's center of gravity than themain one, the displacement of the beams of this pair in space has adifferent amplitude as compared to that of the beams of the main pair.This causes distortions of the symbol. As has already been mentionedabove, motions of a landing deck are in fact periodic oscillations witha frequency of several seconds, that is why the specified symbolconfigurations is also distorted with a certain periodicity, which isrepresentative of the motions of a ship landing deck.

Another embodiment (FIG. 40) of the proposed take-off and landing systeminstalled on the landing deck 3 of the ship 49 comprises sources ofelectromagnetic radiation arranged as in FIG. 17. In this case, thesources I and 8 of electromagnetic radiation constituting the main pairare positioned on the opposite boundaries 10 and 10' of the landing deck3 in the immediate vicinity of the touchdown zone 50 of the aircraft Aon the landing deck 3. The sources 13 and 14 constituting the secondpair are also positioned on the side boundaries 10 and 10' of thelanding deck 3 between the stern edge 52 and the main pair of sources Iand 8, and, finally, the sources 21 and 22 constituting the third pairof sources are positioned on the side boundaries 10 and 10' of thelanding deck 3, like the sources of the first and second pairs, on theother side of the sources I and 8 of the main pair in relation to thesources 13 and 14. The beams 15 and 16 of the sources 13 and 14 ofelectromagnetic radiation indicate the near limit of the touchdown zone50 and the beams 23 and 24 of the sources 21 and 22 indicate the farlimit of the touchdown zone 50 of the aircraft A on the landing deck 3.

Referring to FIG. 17, the embodiment of the take-off and landing systemis different from that of FIG. 40 in the arrangement of the sources, thepositions of the sources 13 and 14 being interchanged with those of thesources 21 and 22.

Motions of the landing deck 3, caused by instability of the ship 49 onthe rough surface of the sea, bring about motion of all sources mountedon the deck 3. In this case, if all sources are mounted on thegyro-stabilized platforms 51, each pair of beams, e.g. the beams 4 and 9of the sources I and 8, carry the information on the heel of the landingdeck 3, as described above.

Since all the sources of electromagnetic radiation are positioned atdifferent distances from the center of gravity of the ship 49, thesources 13, 1 and 21 being placed along the side boundary 10 of thelanding deck 3 and the sources 14, 8 and 22 being placed along theopposite side boundary 10', the beams 15, 4, 23 and 16, 9, 24 of eachgroup of three sources indicate longitudinal angular motions of the sideboundaries 10 and 10' and all together indicate the longitudinal angularmotions of the landing deck 3. A similar arrangement has been mentionedabove, when the embodiment of FIG. 38, comprising two sources ofelectromagnetic radiation on a landing deck of a ship, was described.

The table of distortions of the specified symbol configuration for theembodiment of FIG. 40 is given in FIG. 18 and was described in detailabove. Motions of the landing deck and the sources of electromagneticradiation installed thereupon cause periodic distortions of thespecified symbol configuration indicative of the heel and longitudinalangular motions of the ship landing deck.

One more embodiment (FIG. 41) of the proposed take-off and landingsystem installed on the landing deck 3 of the ship 49 comprises sourcesof electromagnetic radiation arranged as in FIG. 21.

The sources I and 8 of electromagnetic radiation are positioned on theopposite boundaries 10 and 10' of the landing deck 3 in the immediatevicinity of the touchdown zone 50 of the aircraft A on the landing deck3 exactly as illustrated in FIG. 39 and described above. The thirdsource 29 is placed on the stern edge 52 of the landing deck 3 on itscenter line SS, its beam 30 being directed in the course plane C. Thesources 1, 8 and 29 may be mounted on the gyro-stabilized platforms 51.

The beams 4 and 9 of the sources 1 and 8 of electromagnetic radiationcarry additional information about the heel of the landing deck 3, asdescribed above, whereas the beam 30 of the source 29 indicatesup-and-down motions of the stern edge 52 of the landing deck 3 and, incombination with the beams 4 and 9 of the sources 1 and 8, indicateslongitudinal angular motions of the landing deck 3.

These motions are perceived aboard the aircraft A as periodicdistortions of the specified symbol configuration illustrated for thisarrangement of the sources 1, 8 and 29 in FIG. 22 and described indetail above.

Referring now to FIG. 42, an embodiment of the proposed take-off andlanding system comprises the sources of the course and glide slopegroup, landing lights group and marker group. The sources 1, 8 and 29constituting the course and glide slope group are positioned exactly asshown in FIG. 41, their beams 4, 9 and 30 carrying the same informationas described in detail above, that is indicating the deviations of theaircraft A from the estimated take-off or landing path W. These sourcesare mounted on the gyro-stabilized platforms 51.

The sources 35 and 39 constituting the landing lights group arepositioned at the end of the landing deck 3 opposite to its stern edge52. The beams 36 of the source 35 are directed along the side boundaries10 and 10' of the landing deck 3 and indicate these boundaries, whereasthe beam 40 of the source 39 is directed along the center line SS of thelanding deck 3 and indicates this center line. All requirements toinstallation of these sources 35 and 39, as well as to orientation oftheir beams 36 and 40, are given in detail above. The sources 35 and 39are mounted directly on the landing deck without gyro-stabilizedplatforms. In this case, their beams 36 and 40 remain stationary inrelation to the landing deck 3 and indicate all motions of this landingdeck 3.

These motions of the landing deck 3 are perceived aboard the landingaircraft as distortions of the specified symbol configurationillustrated in FIG. 29. The periodicity of these distortions is anindication of the motions of the landing deck 3, its heel andlongitudinal angular motions, as described above.

The sources 43 constituting the marker group are installed on the sideboundaries 10 and 10' of the landing deck 3. In the illustrated example,two of them (43) are placed in the immediate vicinity of the sources Iand 8, and their beams 44 intersect and indicate the flare initiationpoint 45. Two other sources 43 are positioned, in particular, on thestern edge 52 of the landing deck 3. Their beams 44 intersect andindicate the point 45 designating the assigned distance to the sternedge 52 which is the beginning of the landing deck 3. In this case, thepoint 45 produced by the beams 44 of the sources 43 positioned on thestern edge 52 of the landing deck 3 is farther from the stern edge ofthe landing deck than the flare initiation point 45 produced by thebeams 44 of the sources 43 installed in the immediate vicinity of thesources 1 and 8. The sources 43 are also mounted on the gyro-stabilizedplatforms 51.

The beams of the sources of electromagnetic radiation, taken together,form a symbol composed of three simple symbols produced by the beams ofeach group of sources, their specified configuration having beendescribed above, as well as the information carried by the distortionsof this specified configuration of symbols.

It should be kept in mind that said sources of electromagnetic radiationmay be arranged differently, e.g. the sources 43 with the beams 44indicating, on intersection, the flare initiation point 45 may bepositioned both behind and before the sources I and 8, specifically, onthe stern edge 52. Besides, all the sources constituting the markergroup, as well as the sources 1 and 8 of the course and glide slopegroup, may be installed on deck structures of the ship 49 or directly onthe landing deck 3.

It should be once more emphasized that the proposed take-off and landingsystem solves a number of problems of landing an aircraft on a shiplanding deck, which are impossible to solve with the help of traditionalprinciples, and eliminates many a shortcoming inherent in landingsystems being currently used.

First of all, as has been mentioned above, the landing corridor, formedby the beams of the sources of electromagnetic radiation, constitutingthe course and glide slope group, extends the take-off and landingplatform, in this case the landing deck of a ship, and flying anaircraft in this corridor increases the landing safety.

If electromagnetic radiation producing the beams being directed extendedreferences is selected in the visible spectrum, the beams become visibleand perform the functions of the approach and lead-in lights, which areimpossible to install in sea conditions. No currently known system hassuch potentialities. Besides, visible beams are spatially situated nearan aircraft and surround it from all sides, thus increasing the pilot'sconfidence.

The proposed take-off and landing system features high accuracy andmakes it easy to detect motions of a landing deck with an accuracy ofseveral centimeters and, which is particularly important, to see thesemotions, both angular and linear.

Owing to peculiarities of human vision, the pilot is able to notice notonly the motion itself, but the tendency of these motions, too, that isit becomes very easy to predict the next motion, to get ready for thesemotions and to operate flying controls in advance.

Besides, designation of some points in space, which are marker points,permits a very high degree of accuracy in indicating to the pilot theassigned distance to the beginning of the landing deck, as well as theflare initiation point.

Since approaching a marker point is determined by distortions of thesymbol configuration, it is not only the moment of reaching the assigneddistance that can be seen, but also the process of approaching aspecified marker point. And, finally, if the system is visual, theprocess of approaching a specified distance can be monitored visuallyand the pilot can get ready in advance for certain operations, e.g. forinitiation of flaring the aircraft immediately before landing.

This effect cannot be provided by any of existing systems, which isanother important advantage of the proposed system.

Finally, the unified symbol structure provides a means for easyautomation of the landing process as a whole.

Beams of electromagnetic radiation in the above described embodiments ofthe take-off and landing system indicate the course and glide slope ofan estimated take-off or landing path shown for simplicity as a straightline. As has been already mentioned above, the estimated landing pathusually is not rectilinear but broken for the sake of shortening landingdistance and is composed of several legs. Referring now to FIG. 36, theembodiment of the take-off and landing system possesses such anestimated landing path.

The take-off or landing distance may also be reduced by performingtake-off or landing along a curvilinear path. A curvilinear estimatedtake-off or landing path may be assigned by changing the inclination ofthe path produced by electromagnetic beams with respecto to the horizon.

Turning now to FIG. 43, the embodiment of the proposed take-off andlanding system provides for aircraft take-off or landing along acurvilinear take-off or landing path. The sources 1, 8, 13 and 14 ofelectromagnetic radiation are installed exactly as in the embodiment ofFIG. 14 and provided with a means 55 for turning the beams 4, 9, 15 and16. Possible extreme positions of the beams 4, 9, 15 and 16 are shown bya dotted line, whereas the solid line indicates an intermediate positionof these beams 4, 9, 15 and 16.

The means 55 for turning the beams 4, 9, 15 and 16 can synchronouslychange the position of these beams in space. In this case, the positionof the beams 4 and 9 in the glide slope plane G₁ is retained, as well asof the beams 15 and 16 in the plane G₂, and these planes G₁ and G₂continuously change their inclination with respect to the horizon. Theplanes G₁ and G₂ are the steepest when the aircraft A is far away fromthe take-off and landing platform 3 and the flattest when it is close tothe platform 3. Instantaneous position of the estimated take-off orlanding path W' at each instant of time coincides with the curvilinearestimated take-off or landing path W. Referring to FIG. 43, theinstantaneous position of the estimated take-off or landing path W' isshown by two dot-dash lines.

Any of the known devices may be used as the means 55 for turning a beam,e.g. reflecting surfaces, mirrors, prisms, etc. which change theirposition and turn the beams tracing the estimated take-off or landingpath by indicating its course and glide slope at every instant.

The specified symbol configuration, as well as distortions of thisconfiguration look like those of FIG. 15. Deviations of the aircraft Afrom the estimated take-off or landing path W are determined bydistortions of the specified symbol configuration as described above.

Referring now to FIG. 44, one more embodiment of the proposed take-offand landing system provides for aircraft take-off and landing along acurvilinear path. The sources 1, 8 and 29 are installed exactly as inFIG. 21 and provided with a means 55 for turning the beams 4, 9 and 30.As a result the beams 4 and 9 of the sources 1 and 8 turn retainingtheir position in the glide slope plane G and indicate at every instanta new position of this plane G. The beam 30 of the source 29 turns inthe course plane C. In combination, the beams 1, 8 and 30 indicate ateach instant of time the course and glide slope of an aircraft, thustracing the estimated take-off or landing path W of the air craft A.

The specified symbol configuration, as well as distortions of thisconfiguration look like that in FIG. 22. Deviations of the aircraft Afrom the estimated take-off or landing path W are determined bydistortions of the symbol configurations as described above.

Not only the sources of the course and glide slope group may be providedwith means for turning their beams indicating, as described above, ateach instant of time the course and glide slope of the aircraft A flightpart and tracing the curvilinear estimated take-off or landing path W,but also the second additional sources constituting the marker grouptoo. Such a group of marker sources is shown in FIGS. 30 and 31. Thebeams 44 of the sources 43 produce, as described above, the intersectionpoint 45, so-called marker point situated in the course plane C at theassigned distance and indicate that distance. If now each of the sources43 is provided with a beam turning means, the beams 44 start turning andthe point 45 designating the assigned distance starts moving in spaceindicating a different distance at each instant of time. This embodimentof the proposed take-off and landing system is not shown because of itssimplicity, but it can be easily understood since only the beam turningmeans 55 of FIGS. 43 and 44 are added to the above described embodimentof FIGS. 30 and 31. The beams 44 of the sources 43 are turned verticallyso that at each instant of time the point 45 is at the same distancefrom the estimated landing path W in the course plane C. When theestimated landing path W is a straight line, e.g. as shown in FIGS. 21or 34, the marker point 45 moves in a plane parallel to the glide slopeplane G.

The specified symbol configuration produced by the beams 44 of thesources 43 of electromagnetic radiation and distortions of thisconfiguration are described in detail above and illustrated in FIGS. 32and 33. The turning speed of the beams 44 is preset so that the markerpoint 45 moves in space at a preset speed equal to the speed of movementof the aircraft A along the estimated landing path W with allowancebeing made for the wind component.

When the aircraft A moves along the estimated landing path at the presetspeed with proper allowance for the wind component and if theglide-slope speed is equal to the speed of movement in space of themarker point 45, the specified symbol configuration produced by thebeams 44 remains unaltered during the entire flight of the aircraft Aalong the estimated path W.

If the speed of movement of the aircraft A along the estimated path W isless than the speed of movement of the point 45 in space, the specifiedsymbol configuration is distorted and looks like that in the VI squareof FIGS. 32 or 33.

If the speed of movement of the aircraft A along the estimated path W isgreater than the speed of movement of the point 45, the specified symbolconfiguration becomes like that in the VIII square of the same figures.

The above described way of positioning marker sources in combinationwith the course and glide slope group of sources, e.g. the system ofFIG. 21, permits, as shown in FIG. 34, piloting the aircraft A along thecourse and glide slope of an estimated landing path by the symbolproduced by the beams of the sources of the course and glide slope groupand controlling the speed of the aircraft by the symbol produced by thebeams of the sources of the marker group.

In this case, the proposed take-off and landing system provides thepilot with a comprehensive information on the spatial attitude of theaircraft and additionally indicates deviations of the speed of theaircraft A from the assigned landing speed with proper allowance for thewind speed, something no modern landing system can provide. This featureof the proposed system permits sharp reduction in the number ofinstruments required for pilot's orientation, in fact bringing them downto one instrument displaying the information on the distortions of thespecified configuration of symbols produced by the beams of the courseand glide slope group and the marker sources group. If the system ismade visual, the pilot receives visual information by watching theoutside space.

Examples of other embodiments of the proposed take-off and landingsystem ensuring take-off and landing along a curvilinear path can bemultiplied.

There are other methods of creating a symbol ensuring the determinationof an aircraft's attitude in relation to an estimated take-off orlanding path, e.g. symbols which may be called kinematic in contrast tothe above described ones which may be called static symbols.

An example of the proposed take-off and landing system producing akinematic symbol is the embodiment of FIG. 45.

A source I of electromagnetic radiation is positioned similarly to thesources I of Fir. I but is different from it in that the source I ofelectromagnetic radiation is provided with a means 56 for rotating itsbeam 4. As a result, this beam 4 describes a predetermined conicalsurface 57 and produces a symbol looking like a turning straight line.The predetermined conical surface may be closed, like in FIG. 45, oropen, when the beam 4 moves backward, or, in some cases, be a plane.

Referring now to FIG. 46, the embodiment of the proposed take-off andlanding system comprises the source I positioned as in FIG. 2 andprovided with a means 56 for rotating the beam 4. As a result, the beam4 describes a predetermined conical surface 57. In this embodiment, thepredetermined conical surface 57 is closed and shaped as a circularcone. The axis of rotation of the beam 4 at each instant of timecoincides with the estimated take-off or landing path W which may becurvilinear in a general case. Referring to FIG. 46, the estimatedtake-off or landing path W is a straight line.

The rotating beam 4 of electromagnetic radiation, besides, forms thetake-off or landing corridor K, wherein the estimated take-off orlanding path W lies.

The means 56 for rotating the beam 4 may be various devices, inprinciple the same as for turning the beam, e.g. reflecting surfaces,mirrors, prisms, etc. which rotate the beam by changing their position,and it describes the conical surface 57.

The means 56 may rotate the beam 4 and also turn it in the verticalplane G so that the axis of rotation at each instant of time coincideswith the estimated take-off or landing path W.

The symbol produced by the beam 4 has a specified configuration of arotating straight line shown in FIG. 47. The specified symbolconfiguration is given, as before, in the cI square, is produced by therotating projection 5 of the electromagnetic beam 4, and looks like astraight line rotating at a constant angular speed. Rotation isperformed around an arbitrary point 7 coinciding with the point Aindicating the location of the aircraft A. Arrow δ shows the sense ofrotation of the projection 5 of the beam 4.

Referring to FIG. 47, the same notations are used as in FIG. 3.

If the aircraft A deviates from the estimated take-off or landing path Wand is situated to the left of the course, still staying in the glideslope plane G, the symbol configuration is distorted and becomes astraight line rotating at a variable angular speed. These distortions ofthe symbol configuration can be found in the 1I square (FIG. 47). Theangular speed of rotation of the projection 5 around the arbitrary point7 is minimum, when the beam 4 is at a maximum distance from the aircraftA, and grows as the beam 4 approaches the aircraft A. If the aircraft Agoes out of the limits of the take-off or landing corridor K formed bythe rotating beam 4, the symbol configuration is distorted to such anextent that the projection of the beam 4 starts making oscillatorymotions instead of rotating ones (e.g. the mI square of FIG. 47),remaining in a direction opposite to the deviation of the aircraft Afrom the estimated take-off or landing path.

The table (FIG. 47) of distortions of the specified symbol configurationvividly demonstrates how the symbol is distorted depending on thedirection and degree of deviation of the aircraft A from the estimatedtake-off or landing path W and requires no detailed description owing toits simplicity.

It is easy to determine the direction and degree of deviation of theaircraft A from the estimated take-off or landing path W and define thedirection of correction of a current flight path of the aircraft A bythe change of the angular speed of rotation of the projection 5 of theelectromagnetic beam 4.

Referring now to FIG. 48, the embodiment of the proposed take-off andlanding system producing a rotating symbol is conceived as a take-offsystem.

The source I of electromagnetic radiation is positioned on the centerline SS of the take-off and landing platform 3 and provided with a means56 for rotating the beam 4. The axis of rotation of the beam 4 at eachinstant of time coincides with the extimated take-off path W. The sourceI is placed in the immediate vicinity of the lift-off point V of theaircraft A.

An additional source 39 of electromagnetic radiation is positioned atthe end of the take-off and landing platform 3 on its center line SS andalso provided with a means 56 for rotating the beam 40. The beam 40rotates about an axis 58 parallel to the surface of the take-off andlanding platform 3, that is parallel to the center line SS. As a resultof this rotation, two conical surfaces 57 are formed, one being producedby the beam 4 and the other by the beam 40. These conical surfaces 57form the take-off corridor K.

Referring to FIG. 49, the embodiment of the proposed take-off andlanding system producing a rotating symbol is conceived as a landingsystem.

The source I of electromagnetic radiation is positioned on the centerline at the beginning of the take-off and landing platform 3 andprovided with a means 56 for rotating the beam 4. The axis of rotationof the beam 4 at each instant of time coincides with the estimatedlanding path W. The second additional source 39 is installed at the endof the take-off and landing platform 3 on its center line SS andequipped with a means 56 for rotating of the beam 40. The axis 58 ofrotation of the beam 40 is parallel to the center line SS of thetake-off and landing platform 3. Two conical surfaces 57 produced by thebeams 4 and 40 form the landing corridor K. The specified symbolconfiguration produced by the projections of each of the beams 4 and 40of the sources I and 39 of electromagnetic radiation, as well asdistortions of this configuration are shown in FIG. 47 and described indetail above. Deviation of the aircraft A from the estimated take-off orlanding path W can be determined by the distortions of the specifiedsymbol configuration produced by the projection of the electromagneticbeam 4, whereas deviation of the aircraft A from the center line SS ofthe take-off and landing platform 3 can be determined by the distortionsof the specified symbol configuration produced by the projection of thebeam 40 of the source 39 of electromagnetic radiation positioned at theend of the take-off and landing platform 3.

If the proposed take-off and landing system comprises several sources ofelectromagnetic radiation and these sources are provided with beamrotating means, the conical surfaces formed by the rotating beams mayintersect forming an equisignal zone coinciding with the estimatedtake-off and landing path W.

Referring now to FIG. 50, the embodiment of the take-off and landingsystem comprises three sources 1, 8 and 29 of electromagnetic radiationarranged as in the embodiment of the take-off and landing system of FIG.21. All these sources 1, 8 and 29 are provided with means 56 forrotating of the beams 4, 9 and 30 and, as a result, their beams 4, 9 and30 rotate and form the conical surfaces 57 which intersect and form anequisignal zone 59 (shown by hatching in FIG. 50). The estimatedtake-off or landing path W lies within the equisignal zone 59.

The take-off and landing system may, in addition to the sources ofelectromagnetic radiation of FIG. 50 constituting the course and glideslope group, comprise sources constituting the landing lights group,their beams being indications of the center line and boundaries of thetake-off and landing platform, as well as the group of marker sources.It is dealt with in detail above. Referring to FIG. 50, these sources ofelectromagnetic radiation are not shown to avoid overcrowding thefigure.

The specified symbol configuration produced by the projections of thebeams 4, 9 and 30 is more complicated in comparison to that of FIG. 22related to the take-off and landing system of FIG. 21.

This symbol configuration, however, is not difficult to imagine, as wellas its distortions, by simple superimposition of the symbolconfigurations of FIGS. 22 and 47. In this case, the projections 5, 11and 31 (FIG. 22) of the beams 4, 10 and 30 also rotate according to therules laid down above in the description of the table of distortions ofthe specified symbol configuration of FIG. 47.

The above-mentioned symbol, conventionally called kinematic, andproduced by projections of rotating beams offers the pilot accurate andreliable information on the spatial attitude of the aircraft withrespect to an estimated takeoff or landing path. Take-off and landingsystems comprising sources of electromagnetic radiation provided withbeam rotating means permit development of a simple automatic aircrafttake-off and landing system. Their automation is easy because akinematic symbol carries additional information on deviations of anaircraft from an estimated take-off or landing path. This information isa derivative expressed as variations of the angular speed of rotation ofprojections of the beams constituting a symbol. If the wavelength ofelectromagnetic radiation producing the symbol is selected in theoptical spectrum, the system becomes also visual. Since electromagneticbeams are pencil beams, they ensure development of a highly accuratetake-off and landing system surpassing the accuracy of the knownlocalizer and glide slope transmitter systems hundreds of times.

In case the proposed take-off and landing system comprises complete setsof sources of electromagnetic radiation of all groups, that is thecourse and glide slope group, the landing lights group and the markergroup, the beams of sources of electromagnetic radiation of the courseand glide slope group may have a wavelength different from that of thesources of electromagnetic radiation constituting the landing lightsgroup and the sources of the marker group to simplify automaticequipment and to make it more reliable. Multichannel receiving equipmentis installed aboard an aircraft, each of the channels being intended forits own group of sources and thus increasing the equipment's immunity tomutual inteferences resulting from the influence of radiation of onegroup of sources on other groups.

If the selected wavelength of radiation lies in the optical spectrum,another and a very important problem is solved. This is the problem ofvisual monitoring the aircraft's spatial attitude in the process oftake-off or landing. In case take-off or landing is performedautomatically, the pilot is able to follow the operation of theautomatic equipment by watching variations of the symbol configuration,produced by the beams of sources of electromagnetic radiation, andinterfere expeditiously in the process of aircraft control in the eventof great errors in automatic flight control, or even switch promptly tomanual flying in the event of an automatic equipment failure. Thisenables a significant increase in reliability and safety of aircrafttake-off and landing, a sharp decrease in the number of aircraftaccidents, and ensures a reliable stand-by for the system by includingthe pilot into aircraft control, because the reliability of a crew,according to US data, is 10-100 times higher than that of an individualradio command channel. It is the more so because the system retains itsexceptional accuracy even in the case of manual control.

If, in this case, the beams 44 (FIGS. 30 and 31) of the sources 43making up the group of markers designate a number of marker points 45,each of them indicating a definite distance to the take-off and landingplatform, and these beams are produced by electromagnetic radiation inthe visible spectrum, the marker points 45 become visible in space at aconsiderable range and the pilot is able to watch the process of hisaircraft approaching to these points 45 and to get ready for certainoperations. For example, observation of the flare initiation point 45permits exact indication of a point in space, wherein the pilot is toflare the aircraft out and change over to level flight.

As has already been mentioned, to increase the coverage of the systemunder conditions of reduced visibility in fog, electromagnetic radiationproducing pencil beams with a small divergence is to be selected in thefar or near infrared band. Specifically, sources of electromagneticradiation may be molecular CO₂ lasers generating in the wavelength of10.6 mu. Infrared radiation converts atmospheric moisture from drops tovapor, burns channels in fog and in this way moves back the limit of thebeam overall attenuation. The coverage of the system, in this case,grows manyfold. Such sources should be installed first of all todelineate the estimated take-off and landing path, that is to employthem as the sources of the course and glide slope group. For example,referring to FIG. 34, such sources of electromagnetic radiation shouldbe the sources 1, 8 and 29. If, in this case, as has been mentionedabove, the beams of electromagnetic radiation are a combination ofelectromagnetic radiation with wavelengths in the infrared band and thevisible spectrum, the system becomes visual. Infrared radiation burnsthrough the fog and forms a channel wherein the visible beam isdirected.

The accuracy of the proposed take-off and landing system and itscoverage also depend upon the directivity of electromagnetic beams; theygrow with increase in the directivity of the beams producing directedextended references. The coverage of the system grows with increase inthe directivity of beams primarily due to the increase in the distancefrom the take-off and landing platform to the point where theelectromagnetic beams overlap.

Owing to their divergence, electromagnetic beams gradually grow indiameter as they recede from the source and at a certain distance theirdiameters become so large that they overlap.

Thus, if pencil electromagnetic beams with a divergence of about 5° areemployed, the distance to the point of overlapping is of the order of Ikm and grows sharply, when the divergence is decreased. Such distancereaches 200 km with a beam divergence of five angular minutes.

Secondly, with increase in the directivity of electromagnetic beams, theenergy density of electromagnetic radiation also increases in the beamand, consequently, the density of scattered energy increases, too. Thisallows employment of less sensitive receivers aboard an aircraft andfacilitates separation of a useful signal against the background of theenvironment. The accuracy of the system also grows with increase in thedirectivity of electromagnetic beams owing to a decrease in the crosssection of directed extended references produced by theseelectromagnetic beams.

The directivity of electromagnetic beams, as mentioned above, can beachieved either by using sources of electromagnetic radiation, producingbeams with small divergence, e.g. lasers, or by using variouscollimators, e.g. lenses, mirrors, etc.

The directivity of electromagnetic beams is dependent on the wavelengthand grows with its decrease. That is why the thinnest pencil beams areproduced by sources of electromagnetic radiation in the gamma range,primarily, gamma-ray masers.

Laser and maser generated beams are best suited to meet the aboverequirements. Divergence of laser or maser beams amounts to severalangular minutes and in many a case approaches the natural diffractiondivergence. Besides, laser (maser) beams exhibit high density ofelectromagnetic energy that no other electromagnetic source can provide.Finally, lasers (masers) generate, as a rule, in a narrowelectromagnetic spectrum making the selection of a wavelength ofelectromagnetic radiation to lie within an atmospheric windowundoubtedly easier. Lasers (masers) operate on one or severalwavelengths and laser (maser) emission possesses and extremely highspectral density facilitating isolation of a useful signal against thebackground of environment.

The process of discrimination of directed extended references againstthe background of the environment is facilitated when electromagneticbeams producing these references can be modulated. To this end, sourcesof electromagnetic radiation are equipped with modulators. Thesemodulators may be provided either for all sources of electromagneticradiation, included in a take-off and landing system, or for sources ofone of the groups, e.g. the course and glide slope or marker group, orfor some sources of a group, e.g. sources of the main pair, according tothe above described embodiments of the take-off and landing system.

Modulation of electromagnetic radiation may be either frequency oramplitude modulation. When the proposed take-off and landing system ismade as visual, modulation may be just periodic shutting down of a beamwith the result that it disappears periodically.

Such flickering of a beam with a certain frequency significantlyfacilitates the process of visual beam search and detection, because itattracts the pilot's attention.

The frequency of flickering of the order of I Hz increases the pilot'sconfidence in the favorable outcome the take-off or landing because ofits sedative effect on the pilot.

Faster frequency of flickering causes anxiety, whereas slower frequencyis depressing.

Variations of the time interval between flickers may serve to transmitvarious information to the aircraft, e.g. airfield code, magneticlanding heading, etc.

All embodiments of the proposed aircraft take-off and landing system, ashas already been pointed out, are based on a novel principle differentfrom the fundamental principles of all currently employed take-off orlanding systems, including the radio localizer and glide slopetransmitter systems.

This principle consists in employment of directed extended referencesproduced by electromagnetic pencil beams with a small divergence,intended, primarily, to form a symbol of a specified configuration to beperceived aboard an aircraft owing to scattering of energy ofelectromagnetic radiation in the atmosphere.

The foregoing proves that the known and currently used methods ofperforming aircraft take-off and landing cannot ensure the process ofaircraft take-off or landing with the aid of the proposed take-off andlanding system and a new simple and reliable method is to be developedto provide for the entire process of take-off or landing at all stages.

The process of take-off or landing with the aid of the proposed take-offand landing system, whatever embodiment is used of the large variety,starts with the moment an aircraft is brought into the coverage ofextended directed references produced by pencil beams of sources ofelectromagnetic radiation, capture of these directed extendedreferences, and a symbol being formed by said beams.

Such entering the coverage of directed extended references, that is thecoverage of a take-off and landing system, is necessary for performingboth take-off and landing. In the case of take-off, entering thecoverage of the system consists in taxiing the aircraft to the departureline on a take-off and landing platform, then capture is effected of thesymbol produced by the beams of additional sources of electromagneticradiation positioned at the end of the take-off and landing platform, inaccordance with the systems of FIGS. 24, 26, 28, 35.

If, in this case, the wavelength of electromagnetic radiation producingthe beams is selected in the visible spectrum, the pilot is able to seethe beams delineating the side boundaries 10 and 10' or the center lineSS of the take-off and landing platform 3, and places the aircraft A sothat it is on the center line SS of the take-off and landing platform.In this case, the symbol formed by the beams 36 and 40 of the additionalsources 35 and 39 positioned as in one of FIGS. 24, 26 or 28 acquires aspecified configuration. From this moment on, the aircraft A is ready totake off with the aid of the proposed take-off and landing system.

In the case of landing, the aircraft A is lead into the coverage of theproposed take-off and landing system by anone of the known methods ofbringing an aircraft out to the landing heading at an assigned flightlevel with the aid of any known short-range navigation facilities. Theaircraft may, for example, be led out from the rectangular course, ordirectly by signals of airfield homing radio stations, radars, or byground control, etc. After the aircraft is led out to the landingheading at an assigned flight level and at an assigned range from thetake-off and landing platform, it comes within the coverage of thesources of the course and glide slope group installed as in anyone ofthe embodiments of the take-off and landing system. The airbornereceiving equipment captures the system and a symbol is produced in theinstrument; it is one of the above described symbols with aconfiguration determined by the arrangement of sources on the flightplatform. If the wavelength of electromagnetic radiation producing beamsis selected within the visible spectrum, the pilot is able to see thebeams and the symbol. From this moment on the aircraft is ready forlanding with the aid of the proposed take-off and landing system.

It should be once more pointed out that the system may be embodied as atake-off system and as a landing system.

The proposed take-off and landing system is henceforth referred to as"the system" meaning both the take-off and landing versions, but keepingin mind the difference in the arrangement of sources in the twoembodiments.

The foregoing suggests that the processes of bringing an aircraft intothe coverage of directed extended references, both for take-off andlanding, have much in common. However, the process of bringing anaircraft into the coverage of directed extended reference for landing isundoubtedly more complicated and demands greater skill and effort.

If the proposed system comprises one source (e.g. the source I of FIG.2) of electromagnetic radiation, its beam 4 producing a symbol andindicating the course and glide slope of the estimated take-off andlanding path W, the process of bringing the aircraft A into the coverageof this beam for take-off consists in the aircraft A reaching thelift-off point V, the source I being installed in the immediate vicinityof this point. This happens in the process of the take-off run of theaircraft A from the departure line, wherefrom the aircraft startsmoving, to the lift-off point V wherein the aircraft A reaches thelift-off speed. As the aircraft A reaches the lift-off point V, itenters the coverage of a directed extended reference.

In this case, taxiing on the take-off and landing platform is performedwith the aid of any known airfield facilities currently in use, e.g.airfield light equipment. It should be, however, kept in mind thatcapture of a directed extended reference occurs either at the departureline or in the process of approaching the lift-off point V.

As the aircraft approaches the lift-off point (this point is shown inFIG. 35 illustrating an embodiment of the proposed system made as atake-off system), the symbol (FIG. 3) produced by the beam 4 graduallyacquires the specified configuration (cI square) and signifies that theaircraft is on the estimated take-off path W.

If an aircraft lands through the use of a system comprising one sourceof electromagnetic radiation, e.g. as in FIG. 2, after acquisition ofthe beam of this source, the magnitude and direction of deviation of theaircraft A from the course and glide slope of the estimated landing pathare determined by the distortions of the specified symbol configurationproduced by the beam 4 and shown in FIG. 3. If, in this case, the symbolhas the configuration shown in the 1III square, for example, it meansthat the aircraft is to the left and below the estimated landing path.And to bring the aircraft to this estimated landing path, it isnecessary to maneuver in space so as to move the aircraft upwards and tothe right, watching the symbol regain its proper configuration. Themaneuver can be considered completed when the symbol acquires theconfiguration shown in the cI square.

After the symbol acquires the specified configuration the aircraft ispiloted by strictly keeping to this configuration of the symbol.

The aircraft, in this case, flies along the estimated landing path W,tracking very closely the heading and glide slope.

If the proposed system comprises two or more sources of electromagneticradiation, some of them, as mentioned above, form the course and glideslope group (FIGS. 4, 5, 6, 8, 10, 11, 13, 14, 16, 17, 19, 20, 21, 23)and the others, the landing lights group (FIGS. 24, 26, 28), and thegroup of markers (FIGS. 30 and 31).

Let us first consider the process of piloting an aircraft with the aidof the course and glide slope group of sources only. This is justifiedby the fact that an aircraft usually is not piloted using all groups ofsources at a time.

If the proposed system comprises two or more sources of electromagneticradiation, the beams of these sources, as mentioned above, form atake-off or landing corridor by limiting it from different sides (e.g.FIGS. 8, 10, 11, 13, 14, 16, 17, 19, 20, 21, 22).

In this case, before the aircraft is piloted along the estimatedtake-off or landing path, it is necessary to determine the magnitude anddirection of deviation of the aircraft from the take-off or landingcorridor by distortions of the symbol specified configuration, toperform maneuvers to enter this corridor, then correct the aircraft pathso that the symbol acquires the specified configuration and only thenfly the aircraft along the take-off or landing path W by keeping thespecified symbol configuration.

For example, if an aircraft takes off through the use of the proposedsystem made as a take-off system (FIGS. 14, 17 or 21), the distortedsymbol configuration during the take-off run at first corresponds to thecV square (FIGS. 15 and 18) when the aircraft A is on the center line SSof the take-off and landing platform 3 outside the take-off corridor W,or to the squares IV or rV when the aircraft A is, respectively, to theleft or right of the center lines SS of the take-off and landingplatform 3 also outside the take-off corridor K. As the aircraft Aapproaches the lift-off point V, it is first brought into the take-offcorridor K (II squares of FIGS. 15, 18 and 22) and then approaches thelift-off point V. If the aircraft A enters the take-off corridor Kmoving to the left of the center line SS of the take-off and landingplatform 3, the distortion corresponds to the 1II square, when moving tothe right of the center line, it corresponds to the rII square.Corrections of the aircraft's path are to make the symbol acquire thespecified configuration corresponds to the cI square. At this moment,the path of the aircraft A coincides with the estimated take-off pathand the aircraft A starts climbing along this estimated take-off path.

If the aircraft A lands through the use of the same systems (FIGS. 14,17, 21), the process of bringing the aircraft A into the landingcorridor K is similarly performed making use of the distortions of thespecified symbol configuration of FIGS. 15, 18 and 22 and, when thespecified configuration is obtained, the aircraft A starts descendingalong the estimated landing path W. Let us consider by way of example acase when distortions of the symbol configuration correspond to the mIVsquare. In this case, the aircraft A is to the left and below thelanding corridor K. The maneuver to bring the aircraft A into thelanding corridor K is performed so that the aircraft A starts movingupward and to the right. The symbol gradually acquires the configurationcorresponding to the lIII square, which means that the aircraft A isbelow the glide slope and to the left of the course of the estimatedlanding path. Then, the symbol gradually approaches its specifiedconfiguration (the cI square) and the aircraft A approaches to theestimated landing path W.

When the aircraft A is piloted along the estimated take-off or landingpath W, its deviations from this path are also determined by distortionsof the specified symbol configuration.

Various embodiments of the proposed system feature symbols of differentconfigurations depending on the arrangement of sources on the flightplatform 2.

Some embodiments of the proposed system comprise sources positioned onthe center line SS of the take-off and landing platform 3 (FIGS. 2, 5,6, 8, 19, 20, 21, 23). Other embodiments comprise no such sources, butuse sources of electromagnetic radiation arranged on either side of thecenter line SS of the take-off and landing platform 3 (FIGS. 10, 13 and16) arbitrarily or symmetrically about this center line SS (FIGS. 11,14, 17). There exist embodiments comprising both sources placed on thecenter line SS of the take-off and landing platform 3 and sourcesarranged symmetrically on the opposite sides of this center line SS(FIGS. 20, 21 and 23).

When the system comprises one or several sources 1, 8 or 29 (FIGS. 2, 5,6, 8 or 21) of electromagnetic radiation positioned on the center lineSS of the take-off and landing platform 3, the beams 4, 9 or 30 of thesesources 1, 8 or 29 produce projections which, in turn, produce symbolcomponents positioned vertically, when the aircraft A is in the courseplane C (e.g. the projections 5 of FIGS. 3, 7, 9 or the projection 31 ofFIG. 22). In this case, if the aircraft A deviates from the course planeC, these components of a symbol deflect from the vertical and make acertain angle with this vertical (e.g. the lI or rI squares of FIGS, 3,7, 9, 22).

Deflection of symbol's vertical components from the upright position isan easy and simple indication of not only the deviation of the aircraftA from the course of the estimated take-off or landing path W, but alsoan indication of the direction and magnitude of this deviation.Respective tables of distortions of the specified configuration of asymbol are a vivid illustration of this.

If a symbol is produced by the beams 4, 9, 15, 16, 23, 24 (FIGS. 10, 11,13, 14, 16, 17) of the sources 1, 8, 13, 14, 21, 22 of electromagneticradiation arranged symmetrically about the center line SS of thetake-off and landing platform 3, deviations of the aircraft A result inupsetting the symmetry of the specified symbol configuration, e.g. FIGS.12, 15, 18 (lI, rI, lII, rII, lIII, rIII squares).

To bring the aircraft A back to the course of the take-off or landingpath W, upright position of the symbol's components or the symbol'ssymmetry is to the restored.

Deviations of the aircraft A from the glide slope of the take-off orlanding path W are also determined by distortions of the specifiedsymbol configuration. There are also two methods of detecting thesedeviations.

If the proposed system comprises one or several sources ofelectromagnetic radiation with beams oriented in the glide slope plane,e.g. the systems of FIGS. 2, 4, 5, 6, 7, 10, 11, 13, 14, 16, 17, 19, 20,21, 23, their projections producing the horizontal components of asymbol, any deviation of the aircraft A from the glide slope of theestimated take-off or landing path W makes these components deflect fromthe horizontal direction and make a certain angle therewith. This isalso vividly illustrated in respective tables of distortions of thespecified symbol configuration (FIGS. 3, 7, 12, 18, 22).

A second method of determination of deviations of the aircraft A fromthe glide slope of the estimated take-off or landing path W is employed,when the beams of the sources of electromagnetic radiation of theembodiment of the proposed system used in this case feature asymmetrical configuration. These embodiments are shown in FIGS. 8, 14,17 and 23.

In such cases, the specified symbol configuration symmetry about thehorizontal is upset when the aircraft A deviates from the glide slope ofthe estimated take-off or landing path W (FIGS. 9, 15, 18).

It is necessary to restore either the horizontal position of thesecomponents or the symbol's symmetry to bring the aircraft A to the glideslope of the estimated take-off or landing path W.

As has already been mentioned above, the beams of sources ofelectromagnetic radiaton delineate various limits of the take-off orlanding corridor K, e.g. its side, upper and lower limits. If theaircraft A goes out of the limits of this corridor K, the symbolproduced by the beams of sources of electromagnetic radiation isdistorted so that the beam projections acquire some common direction.For example, the projections 5, 11, 17, 18, 25, 26 (FIG. 18) andprojections 5, 11, 31 (FIG. 22) in the tIV square are directed to theleft and upward of their arbitrary points 7, 12, 19, 20, 27, 28 and 7,12, 32. This means that the aircraft A is outside the take-off or alanding corridor K, to the right and below this corridor, and the taskis now to return it into this corridor. The process of returning theaircraft A into the take-off or landing corridor K is described indetail above.

If the aircraft A is in the course plane C and deviates from the glideslope of the estimated take-off or landing path W, e.g. downward, andgoes beyond the lower limit of this corridor K, the projection 31 (FIG.22) of the beam 30 (FIG. 21) changes its position for an opposite one,still remaining vertical. This moment indicates that the aircraft Acrosses the lower limit of the take-off or landing corridor K. Theprojections 5 or 11 (FIG. 22) also change their positions for theopposite in the same way, when the aircraft A goes over (FIG. 21) to theright or left side limit of the take-off or landing corridor K, stillstaying in the glide slope plane.

If, in this case, the beams 4, 9, 15, 16 (FIG. 14) of the sources 1, 8,13 and 14 of electromagnetic radiation or the beams 4 and 9 (FIG. 23) ofthe sources 1 and 8 define the side boundaries 10 and 10' of thetake-off and landing platform 3, the aircraft A going beyond the sidelimits of the take-off or landing corridor K is at the same timeevidence of the aircraft A being outside the side boundaries 10 and 10'of the take-off and landing platform 3. If, in this case, the path ofthe aircraft A is not corrected, the aircraft A is to miss the take-offand landing platform 3 and safe landing is not ensured.

Approaching the limits of the take-off or landing corridor K by theaircraft A may be detected by the direction and degree of distortion ofthe specified symbol configuration, e.g. the tables of distortions ofFIGS. 15, 18, 22 clearly indicate that the l squares correspond to theaircraft A being situated closer to the left side limit of a take-off orlanding corridor. The r squares, on the contrary, indicate that theaircraft A is closer to the right side limit.

If the proposed system comprises the landing lights group of sources(FIGS. 24, 26, 28) besides the course and glide slope group of sources(FIGS 1, 2, 4, 5, 6, 8, 10, 11, 13, 14, 16, 17, 19, 20, 21, 23), thebeams of these sources and the symbol produced by these beams ensure theentire take-off process from the beginning of the take-off run to thelift-off, as well as the entire landing process at the last stage,immediately before the aircraft A touches the surface of the take-offand landing platform 3, and its landing run.

As mentioned above, take-off of the aircraft A starts with the moment ofcapturing the beams 36 and/or 40 (FIGS. 24, 26, 28) of the additionalsources 35 and/or 39.

When the beams 36 alone are available (FIG. 24), the course of theaircraft A is maintained by the symmetry of the symbol (FIG. 25)produced by the beams 36 of electromagnetic radiation. The receiver ofelectromagnetic radiation is to be installed aboard the aircraft so thatit is somewhat higher than the plane of orientation of the beams 36. Inthis case the specified symbol configuration of FIG. 25 placed in the cIsquare is distorted and resembles the one in the cII square. In thiscase, deviations from the course plane C are perceived as upsetting thesymmetry (lII or rII squares). The aircraft A is run to take-off alongthe center line SS of the take-off and landing platform 3 up to thelift-off point by preserving the symbol symmetry about the vertical 6.After the aircraft A lifts off the surface of the take-off and landingplatform 3, take-off is performed by the beams of the sources of thecourse and glide slope group, e.g. through the use of the system of FIG.14 or 23 with the aid of the symbol produced by the beams of the sourcesof these systems. For some time, the symbol produced by the beams 36 ofthe additional sources 35 may be used.

If the source 39 alone (FIG. 26) is available from the group ofadditional sources, take-off is performed by keeping the specifiedsymbol configuration produced by the beam 39 of FIG. 27 in the cI squareand holding this beam 39 in the course plane.

If the source 35 and 39 are available at a time (FIG. 28), take-off isperformed by distortions of the specified configuration of the symbolproduced by the beams 36 and 40 shown in the cI square of FIG. 29.

For some time, after the aircraft A lifts off the surface of thetake-off and landing platform 3, the symbol produced by the beams 36 and40 may be used for orientation.

When the aircraft A lands through the use of the symbol produced by thebeams of the sources of eletromagnetic radiation of any embodiment ofthe course and glide slope group, e.g. the system of FIG. 17 or 21, thebeams 36 and/or 40 (FIGS. 24, 26, 28) of the additional sources 35and/or 39 are captured, and the pilot is able to proceed to piloting theaircraft by the symbol produced by these beams 36 and/or 40.

However, piloting the aircraft by the symbol produced by these beams 36and/or 40 starts after flying over the flare initiation point wherefromthe aircraft is flattened out. In this case, the aircraft A is flowntowards the surface of the take-off and landing platform 3 by thestraightening configuration of the symbol, approaching the specifiedconfiguration (FIGS. 25, 27, 29). When the symbol acquires the specifiedconfiguration, the aircraft touches the surface of the take-off andlanding platform 3.

Landing run is performed similarly to the take-off run. And deviation ofthe aircraft A from the course is determined by deflections of thevertical component of the symbol produced by the projection 41 (FIGS.27, 29) of the beam 40 (FIGS. 26, 28) from the upright position or byupset symmetry of the symbol produced by the projections 37 (FIGS. 25,29) of the beam 36 (FIGS. 24, 28).

If the aircraft A banks in the process of take-off or landing, thisbanking is perceived as a turn of the entire symbol as a whole. In thiscase, the symbol is turned about the point A (FIGS. 7, 9, 12, 15, 18,22, 25, 27, 29).

The configuration of a symbol turned about the point A is not shown forit can be easily imagined. During such a turn, the horizontal componentsof the symbol, e.g. the projections 5 and 11 of FIGS. 12, 18, 22 of thebeams 4 and 9 of FIGS. 10, 11, 16, 17, 19, 21 are as though deflectedfrom the horizontal direction as viewed by an observer. In reality,these projections retain their horizontal direction and a spatial turnis performed by the banking aircraft A. To recover, the controls of theaircraft A are to be operated so that the projections 5 and 11 of thebeams 4 and 9 are positioned horizontally. As mentioned above, thisfeature of the proposed system significantly facilitates the process ofpiloting especially when the system is visual, because the symbolproduces so-called cross-bar. it is essential that the range to thetake-off and landing platform should be indicated in the course oflanding. It is currently determined with the aid of radars by the momentof overflying ground-based radio markers. In the proposed system, theassigned range to the take-off and landing platform 3 (FIGS. 30 and 31)is determined by passing the marker points 45 produced by theelectromagnetic beams 44. These marker points 45 indicated the range tothe outer, middle and inner marker locators, as well as the flareinitiation point.

In the process of landing, the aircraft A successively passes thesepoints and the moment of passing each of them is determined bydistortions of the specified symbol configuration dependent on theorientation of the beams 44 (FIGS. 32 and 33). The moment of reachingthe assigned range occurs when the symbol acquires the specifiedconfiguration (the VII square). If the system is visual, the pilot isable to watch each marker point even at long distances, as well as theentire process of approaching this point. The proposed system ensures avery high accuracy of ranging, no worse than 10-15 m. This is ofparticular value for determining the aircraft flare initiation, since itpermits the aircraft to be lead to the flare initiation point with ahigh accuracy of 0.5-1 m in altitude and 10-15 m in range.

If the aircraft A lands with the aid of the proposed system and thebeams of the sources of electromagnetic radiation of the system form abroken path consisting of several legs, the aircraft is at first flownalong a leg of the landing path with the glide slope set at one angle bykeeping the specified configuration of the symbol produced by the beamsof the additional sources indicating the course and glide slope of thisleg of the path, then it is piloted along the next leg of the path withthe glide slope set at another angle by also keeping the specifiedconfiguration of the symbol produced by the beams of the next additionslsources of electromagnetic radiation, etc. The aircraft is thussuccessively piloted along separate legs of the landing path and then,finally, it is piloted along the last leg by the specified configurationof the symbol produced by the beams of the sources of electromagneticradiation installed at the beginning of the take-off and landingplatform, whereupon the process of descending along the glide slope iscompleted and landing is performed. The course of the broken landingpath is maintained the same at all stages. For example, when the systemof FIG. 36 is used, its beams 4, 9, 30, 4', 9', 30' being indications ofthe estimated landing path W with one bend, the aircraft A is firstflown along the steeper leg W₂ of this path by keeping the specifiedconfiguration of the symbol produced by the beams 4', 9' and 30', thenit is transferred gradually to a flatter leg W₁ of the path by alsokeeping the specified configuration of the symbol produced by the beams49 and 30. Since in this embodiment of FIG. 36 the sources 1', 8' and29' are arranged like the sources 1, 8 and 29, the specified symbolconfiguration looks the same for both legs of the estimated path of FIG.22.

When piloting the aircraft along the steeper leg W₂, the symbol producedby the beams 4', 9' and 30' is maintained in the position shown in thecI square of FIG. 22. Then, as the aircraft approaches the second leg W₁of the path, it is piloted by the symbol produced by the beams 4, 9 and30 by also maintaining its configuration shown in the cI square of FIG.22.

When switching over to piloting the aircraft along the flatter leg W₁,the symbol produced by the beams 4', 9' and 30' is given up and theaircraft is then piloted by the symbol produced by the beams 4, 9 and30.

Each step of the method ensuring take-off and landing of the aircraft Athrough the use of any embodiment of the proposed system is convered indetail above.

Let us once more outline briefly the sequence of all steps.

The process of take-off of the aircraft A with the aid of any embodimentof the proposed system made as a take-off system consists, as mentionedabove, in bringing the aircraft into the coverage of extended directedreferences produced by the beams 36 and/or 40 of the additional sources35 and/or 39 of electromagnetic radiation positioned, for example, as inFIGS. 24, 26, 28. Then, the aircraft A performs its take-off run to thelift-off point V where it reaches the assigned lift-off speed and movesalong the estimated take-off path W climbing along the path designatedby the beams of the sources of electromagnetic radiation of the courseand glide slope group made as in one of the embodiments of the proposedsystem, e.g. of FIG. 17, 21 or 25. At all stages, the pilot keeps thespecified symbol configuration of FIGS. 29, 18 and 22.

The process of landing is absolutely similar with the reversed sequenceof steps.

At first, the aircraft A is brought into the coverage of directedextended references produced by the beams of the sources of the courseand glide slope group positioned as in one of the embodiments of thesystems (FIGS. 2, 4, 5, 6, 8, 10, 11, 13, 14, 16, 17, 19, 20, 21, 23,34), then the direction and magnitude of the deviation of the aircraft Afrom the landing corridor K are determined by the distortions of thespecified symbol configuration (FIGS. 3, 7, 9, 12, 15, 18, 22) theaircraft is lead into this corridor and, maintaining the specifiedconfiguration of the symbol which corresponds to the aircraft A being onthe estimated landing path W, descent is started by piloting theaircraft along this path W. The moment of passing within the assignedrange from the take-off and landing platform 3 is determined by themarker points 45 produced by the beams 44 of electromagnetic radiation(FIGS. 30 and 31), e.g. the range to the outer, middle and inner markerlocators, while the aircraft approaches the flare initiation point alsodesignated by the marker point 45. The moment of passing a marker pointis determined by reaching the specified configuration of the symbolproduced by the beams 44 of FIGS. 32 or 33. Then, the aircraft A isflattened out and piloted by the symbol produced by the beams 36 and/or40 of the additional sources 35 and/or 39 of FIGS. 25, 27, 29. When thesymbol acquires the specified configuration, the aircraft A touches thesurface of the take-off and landing platform 3. The landing run isperformed by keeping the specified configuration of the symbol (FIGS.25, 27, 29).

As the foregoing indicates, the basic principle of piloting the aircraftA with the aid of the proposed system is the principle of maintainingthe specified symbol configuration. And all deviations of the aircraft Afrom the estimated take-off or landing path W are eliminated ifdistortions of the specified symbol configuration are corrected.

The proposed system, as mentioned above, may be employed to performlanding of the aircraft A on the deck 3 of the ship 49. In this case(FIGS. 37, 38, 39, 40, 41, 42), it is located on the landing deck 3 ofthis ship 49. When installed on the landing deck 3, the system carriesadditional information on angular and linear motions of the deck 3caused by rough sea surface in addition to the information about thespatial attitude of the aircraft A described in detail above. Thisinformation is manifested as periodic distortions of the specifiedconfiguration of the symbol produced by the beams of the sources ofelectromagnetic radiation installed on the surface of the landing deck 3of the ship 49. Periodic distortions of the specified symbolconfiguration are an indication of periodic deviations of the aircraft Afrom the estimated landing path W fluctuating in space about its middleposition. All possible motions of the landing deck 3 have been describedabove.

Not only linear motions of the landing deck 3 in places of location ofthe sources of electromagnetic radiation, but also angular motions ofthis deck 3 can be easily determined by distortions of the specifiedsymbol configuration. Linear motions of the landing deck may be detectedby distortions of the specified configuration of the symbol produced bythe beams of the sources of electromagnetic radiation of any of thesystems of FIGS. 37, 38, 39, 40, 41, 42. The heel of the landing deckmay be easily detected by watching periodic turns of the symbol, asmentioned above, produced by the beams of the sources of electromagneticradiation positioned as in FIGS. 39, 40, 42 and 41. The components ofthis symbol produced by the beams 4 and 9 of the sources 1 and 8 deviateperiodically from the horizontal direction. Longitudinal angular motionsof the landing deck 3 may be easily detected by periodic repetitions ofdistortions of components of the symbol produced, for example, by thebeams 4 and 9 of the sources 1 and 8 of electromagnetic radiationpositioned as in FIGS. 38 or the beams 23, 4, 15 and 24, 9, 16 of thesources 21, 1, 13 and 22, 8, 14 arranged as in FIG. 40. As the foregoingexamples indicate, these sources are installed on the landing deck 3along the center line SS or parallel thereto.

These periodic motions of the landing deck are, as a rule, less inamplitude than the dimensions of the landing corridor W, and in thecourse of landing the aircraft A, therefore, flies within this landingcorridor.

A special note should be made of the peculiarities of take-off orlanding of the aircraft A through the use of the embodiments of theproposed system (FIG. 44) ensuring its take-off or landing along acurved path W, as well as the embodiments of the proposed system (FIGS.45, 46, 48, 49, 50) producing a kinematic symbol.

The use of the embodiment of the system (FIG. 44) ensuring take-off orlanding of the aircraft A along a curved path W leaves the take-off orlanding method unaltered, since the pilot does not see the turns of thebeams 4, 9 and 30 of the sources 1, 8 and 29 of electromagneticradiation but perceives aboard the aircraft A only distortions of thespecified configuration of the symbol (FIG. 22) produced by these beams(4, 9 and 30). His mission is to maintain the specified configuration ofthe symbol (the cI square of FIG. 22) and, in this case, the aircraft Aflies automatically along the curved path W, its shape being set by thesystem.

In case another embodiment of the proposed system is employed,comprising the marker sources 43 (FIG. 30, 31) of electromagneticradiation, their beams 44 being turned to move the marker point 45 inspace at an assigned speed corresponding to the speed of movement of theaircraft A along the estimated landing path W, the aircraft A is pilotedalong the estimated landing path W at a speed ensuring constantconfiguration of the symbol produced by the beams 44.

If the symbol is distorted and acquires the configuration shown in theVI square, this means that the speed of the aircraft A becomes less thanthe assigned speed of movement of the aircraft A along the estimatedlanding path W.

If the symbol is distorted and acquires the configuration shown in theVIII square, this means that the speed of movement of the aircraft Abecomes more than the assigned. The speed of flight of the aircraft A iscorrected by the distortions of the specified symbol configuration inorder to maintain the specified configuration. In this case, theaircraft flies at an assigned speed.

In case an embodiment of the proposed system (FIGS. 45, 46, 48, 49 and50) producing a kinematic symbol is employed, no additional steps arerequired and the essence of the forementioned steps is not changed too.The basic step is still maintaining the specified symbol configurationof a somewhat different type (FIG. 47). Peculiarities of thisconfiguration have been described in detail above.

As has been already mentioned, the beams of sources of electromagneticradiation may be produced by electromagnetic radiation of variouswavelengths as well as provided with modulators. These features of theproposed system leave the method of take-off or landing absolutelyunaffected; they enable the pilot to orient with the aid of the proposedsystem.

Visual embodiments of the proposed system should be particularly pointedout. In these cases, all steps in the process of piloting the aircraft Aare performed visually.

The proposed take-off and landing system is developed as a unifiedsystem requiring no additional or auxiliary subsystems. It ensures allstages of aircraft take-off and landing. The system permits not onlypiloting an aircraft along the estimated take-off or landing path,maintaining the course and glide slope, but also performing take-off runof the aircraft and its landing run, as well as determination of theassigned distance to the take-off and landing platform. Sameinstrumental means is used during all stages of take-off and landing.Such an instrumental means is the symbol of a specified configuration,produced by beams of electromagnetic radiation.

The symbols of any embodiment of the proposed system look principallyalike when produced by the course and glide slope group of sources, aswell as by the landing lights group and the group of markers. Thispermits the use of a single principle of orientation al all stages oftake-off and landing and constitutes the basic advantage over knownsystems.

First of all the extremely high accuracy and ease of aircraft pilotageensured by the proposed system are to be emphasized. As mentioned above,all embodiments of the system ensure detection of the deviation of theaircraft A from the extimated take-off or landing path W within severalcentimeters, as well as bringing the aircraft to the flare initiationpoint with an accuracy of 0.5-1 m in altitude and 10-15 m in range,something no currently used landing system can do, including theinternational ILS system. Specifically, the proposed system is 100-1,000times more accurate than any of the known systems.

Besides, such accuracy of the proposed system is far higher than therequirements as to the permissible vertical deviation of the aircraft inthe area of the runway threshold, put forth in the draft ICAO programfor development of a new landing approach system.

The proposed take-off and landing system may be purely instrumental orvisual by selecting proper sources of electromagnetic radiation. Evenwhen visual, the proposed system remains a reliable instrumental means,since it ensures pilotage of an aircraft with a predetermined accuracy.In this case, no additional equipment is installed aboard the aircraft.

The strong emphasis placed on visual landing systems by experts is amatter of common knowledge. Thus, French and US specialists believe thatthe problem of all-weather landing does not necessarily exclude thepilot from taking part in aircraft control, since reliability of a crewis 10-100 times higher than the reliability of a radio channel.

It should be kept in mind that even with a visual system the aircraftmay carry proper receiving equipment and high-accuracy automaticfacilities. In this case, the pilot gets a reliable means of checkingautomatic equipment operation and is able to change over to manualflying at any moment.

The advantages of visual embodiments of the proposed system are evident,because, in this case, the system becomes more reliable since, as far asis known, changing over from flying on instruments to visual flying andobservation of the outside space requires a period of 3-5 sec necessaryfor visual accomodation and identification of ground objects. A modernaircraft covers from 150 to 200 m during this time interval. The periodbecomes longer during night landung.

Besides, the proposed system produces a take-off or landing corridorformed by electromagnetic beams, acting, in visual embodiments, asapproach and lead-in lights and provide favourable conditions for apilot to orient in space. This advantage of the system becomes stillmore evident on board a ship, when no other means can be used to provideapproach and lead-in lights at sea.

The possibility of designating marker points at sea is also an undoubtedadvantage of the system.

Embodiments of the proposed system, adapted to be installed on thelanding deck of a carrier ship ensure reliable information on linear andangular motions of the landing deck in rough sea conditions, somethingno other known radio system can provide.

Besides, the proposed take-off and landing system permits designation ofthe horizon for a landing aircraft and determination of this bank,another thing no other known radio system can provide.

The photograph of FIG. 51 shows the arrangement of the proposed systemon an airfield and gives an idea of what a take-off or landing corridorproduced by electromagnetic pencil beams looks like. The photographillustrates the embodiment of the system of FIG. 21. In the photograph,all beams are directed upward, which means that the point, wherefrom thepicture was taken, lies below the corridor formed by electromagneticbeams. This photograph corresponds to the cIV square of FIG. 22 with theonly difference that the beam 30 (FIG. 21) of the source 29 ofelectromagnetic radiation positioned on the center line SS of thetake-off and landing platform 3 is made up of two parallel beams, one ofthem being a back-up.

The photograph of FIG. 52 shows a symbol produced by electromagneticbeams of the embodiment of FIG. 34. The picture was taken from thecockpit of an aircraft landing through the use of the proposed systemfrom a distance of 9 km to the take-off and landing platform.

The proposed system permits employment of a reliable and easy method offlying an aircraft along the estimated take-off or landing path,consisting exclusively in continuous maintaining the specified symbolconfiguration, resulting in the aircraft's flying along the estimatedtake-off or landing path. The method is universal for all legs of thispath, a feature no other currently used method of aircraft take-off orlanding possesses.

It can be thus said with confidence that the proposed take-off andlanding system not only fulfils the basic requirements of the draft ICAOprogram for development of a new landing approach system, but alsooutperforms the program requirements.

The principle advantage of the proposed system lies in its capability tosolve the problem of take-off. And, finally proper selction of sourcesof electromagnetic radiation can make the system both visual andinstrumental.

In summary, it might be well to point out that the proposed take-off andlanding system comprising lasers as sources of electromagnetic radiationmay be installed on any airfield in 2 or 3 hours and be ready foroperation immediately thereafter.

What is claimed is:
 1. An aircraft take-off and landing system of thetype which provides the pilot with information relating to the locationof a desired take-off and landing platform and the glide slope thereto,comprising:at least one source of electromagnetic radiation withinpreselected wavelength limits one of which is visible and directedskywards for producing a beam of said electromagnetic radiation which isa pencil beam with a divergence less than 5°, and means for rotating thebeam of said at least one source for making said beam describe a closedconical surface, within which said desired take-off or landing pathlies, thereby producing a symbol visually appearing to the pilot as astraight line rotating at a variable angular speed whereby said speed isa function of the deviation of the aircraft from said take-off andlanding platform glide slope.
 2. A take-off system as claimed in claim1, wherein said at least one source of electromagnetic radiationcomprises:a main source of electromagnetic radiation, positioned on atake-off and landing platform, on its center line, in the immediatevicinity of the aircraft's lift-off point on the surface of the take-offand landing platform; a means for rotation of the beam of said mainsource of electromagnetic radiation, connected to said main source andensuring uniform rotation of said main beam beam, making said main beambeam describe a closed conical surface as a circular cone; an axis ofrotation of the beam of said main source of electromagnetic radiation,coinciding, at each instant of time, with said take-off path; a symbolproduced by said beam of the main source, having, when an aircraft is onsaid estimated take-off path, a specified configuration looking like aline rotating at a constant angular speed; an additional source ofelectromagentic radiation positioned on said take-off platform in theimmediate vicinity of the end of said take-off and landing platform onthe center line of said take-off and landing platform; a means forrotation of the beam of said additional source of electromagneticradiation connected to said additional source and ensuring uniformrotation of said additonal source beam with the result that saidadditional source beam describes a closed conical surface as a circularcone; an axis of rotation of said beam of said additional source ofelectromagnetic radiation, parallel to the surface of said take-off andlanding platform and extending along the center line of said platform; asymbol produced by said beam of the additional source, having, when anaircraft is on the surface of said take-off and landing platform on itscenter line, a specified configuration looking like a line rotating at aconstant angular speed;
 3. A landing system as claimed in claim 1,wherein said at least one source of electromagnetic radiationcomprises:a main source of electromagnetic radiation positioned on atake-off and landing platform on its center line, at the beginning ofsaid take-off and landing platform; a means for rotation of the beam ofsaid main source, connected to said main source and ensuring uniformrotation of said main source beam with the result that said main sourcebeam describes a closed conical surface as a circular cone; an axis ofrotation of the beam of said main source of electromagnetic radiation,coinciding, at each instant of time, with said landing path; a symbolproduced by said beam of the main source, having, when an aircraft is onsaid estimated landing path, a specified configuration looking like aline rotating at a constant angular speed; an additional source ofelectromagnetic radiation, positioned on the flight platform in theimmediate vicinity of the end of said take-off and landing platform onthe center line of said take-off and landing platform; a means forrotation of the beam of said additional source of electomagneticradiation, connected to said additional source and ensuring uniformrotation of said additional source beam with the result that saidadditional source beam describes a closed conical surface as a circularcone; an axis of rotation of said beam of said additional source ofelectromagnetic radiation parallel to the surface of said take-off andlanding platform and extending along the center line of said platform; asymbol produced by said beam of the additional source, having, when anaircraft is on the surface of said take-off and landing platform on itscenter line, a specified configuration looking like a line rotating at aconstant angular speed.
 4. A landing system as claimed in claim 1,wherein said at least one source of electromagnetic radiationcomprises:a first source of electromagnetic radiation, positioned on thetake-off and landing platform on its center line at the beginning ofsaid take-off and landing platform; second and third sources ofelectromagnetic radiation, arranged on said flight platform at thebeginning of said take-off and landing platform symmetrically about itscenter line and behind said first source of electromagnetic radiation onthe side boundaries of said take-off and landing platform; and furthercomprising a means for rotation of the beams of all of said threesources of electromagnetic radiation, operably connected to each of saidsources of electromagnetic radiation with the result that each of saidbeams describes a closed circular conical surface; said second and thirdsources and said means for rotation being arranged such that the axis ofrotation of the beam of said second and third sources extend in a commonglide slope plane; said first source and said means for rotation beingarranged such that the axis of rotation of the beam of said first sourceof electromagnetic radiation is oriented in a course plane and extendingalways below said glide slope plane, wherein said course plane islocated perpendicularly to and along the center line of said take-offand landing platform; and said conical surfaces produced by the beams ofall said three sources of electromagnetic radiation, forming, onintersection, an equisignal zone wherein the estimated landing pathlies.
 5. A take-off and landing system as claimed in claim 1, whereinsaid at least one source of electromagnetic radiation is provided with amodulator.
 6. An aircraft take-off and landing system of the type whichprovides the pilot with information relating to the location of adesired landing platform and the glide slope thereto, comprising:asource of electromagnetic radiation, positioned on the center line ofsaid take-off and landing platform for producing a pencil beam of saidelectromagnetic radiation within preselected wavelength limits one ofwhich is visible, said beam being directed skywards and having adivergence less than 5°; a means for rotation of the beam of said sourceof electromagnetic radiation, connected to said source and ensuringuniform rotation of its beam, making said beam describe a closed conicalsurface as a circular cone; and said source and said means for rotationbeing arranged such that the axis of rotation of said beam ofelectromagnetic radiation coincides with said glide slope; whereby asymbol produced by said beam of electromagnetic radiation, when anaircraft is on said glide slope, appears as a line in space rotating ata constant angular speed.